tag:theconversation.com,2011:/fr/topics/brain-function-27755/articlesBrain function – The Conversation2023-05-02T14:59:59Ztag:theconversation.com,2011:article/2047022023-05-02T14:59:59Z2023-05-02T14:59:59ZConcussion: almost half of people still show signs of brain injury after six months<figure><img src="https://images.theconversation.com/files/523828/original/file-20230502-1704-vb0nir.jpg?ixlib=rb-1.1.0&rect=7%2C7%2C4985%2C3735&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Our study found changes in the way the thalamus functioned in people who'd had concussion.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-rendered-medically-accurate-illustration-thalamus-1292650525">SciePro/ Shutterstock</a></span></figcaption></figure><p>Around <a href="https://brain-amn.org/global-incidence-of-tbi/#:%7E:text=In%20conclusion%2C%2069%20million%20people,suffer%20a%20severe%20TBI%20annually.">56 million people globally</a> suffer a concussion each year. It’s common for concussion to cause <a href="https://www.mayoclinic.org/diseases-conditions/concussion/symptoms-causes/syc-20355594">short-term symptoms</a> such as a headache, nausea, sensitivity to light and problems concentrating. </p>
<p>But many people also struggle with long-term symptoms – including fatigue, trouble sleeping and concentrating, and emotional distress. <a href="https://onlinelibrary.wiley.com/doi/10.1111/acem.13844">Previous research</a> found that clinicians estimated one in ten people might experience long-term symptoms after a concussion. </p>
<p>But our recent study estimates that post-concussive symptoms are far more common. Our study, published in <a href="https://academic.oup.com/brain/advance-article/doi/10.1093/brain/awad056/7051141">Brain</a>, found that almost half of people who suffered a concussion had not fully recovered six months after their injury. </p>
<p>To conduct our study, we analysed brain scans from over 100 patients who had recently experienced concussion from all across Europe. These brain scans were conducted using a technique called resting-state functional MRI (fMRI). </p>
<p>A resting-state fMRI measures brain activity when a person is at rest, which can be used to understand how different regions of the brain communicate. This allows us to understand if the brain is functioning as it should or if there are problems with a person’s brain connectivity.</p>
<p>A resting-state fMRI can also tell us more than a CT scan or MRI might. While these types of scans are often given to concussion patients, both only look for structural changes in the brain – such as inflammation or bruising. </p>
<p>Such changes often don’t occur in mild concussion cases soon after injury, which may lead clinicians to believe no brain damage has occurred. But a resting-state fMRI can show us more subtle changes in brain function – and may help us better predict who is more likely to develop long-term symptoms. </p>
<p>In our analyses, we specifically looked for changes in a region in the centre of the brain called the thalamus. This region is important in integrating sensory information and relaying it throughout the entire brain. </p>
<p>The thalamus is also thought to be <a href="https://link.springer.com/article/10.1007/s11065-020-09474-0/figures/2">very vulnerable</a> to the kind of external force that leads to concussion (such as a fall or blow to the head). </p>
<p>Our research found that concussion was associated with increased functional connectivity between the thalamus and the rest of the brain very shortly after injury, when compared to 76 healthy control subjects. </p>
<p>In other words, the thalamus was trying to communicate more as a result of the injury. This was despite routine MRI and CT imaging showing no structural changes in the brain.</p>
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<img alt="Two football players lie on the ground holding their heads." src="https://images.theconversation.com/files/523829/original/file-20230502-28-u2s167.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523829/original/file-20230502-28-u2s167.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523829/original/file-20230502-28-u2s167.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523829/original/file-20230502-28-u2s167.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523829/original/file-20230502-28-u2s167.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523829/original/file-20230502-28-u2s167.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523829/original/file-20230502-28-u2s167.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The thalamus may be particularly sensitive to the kind of forces that cause concussions.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/lubin-poland-june-05-2014-michal-197028332">Dziurek/ Shutterstock</a></span>
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<p>While many of us would assume that more connectivity in the brain is a good thing, research looking at <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664441/">more severe head injuries</a> indicates that greater connectivity between brain regions might actually be a sign of the brain trying to compensate and offset damage across the brain.</p>
<p>We also found that almost half of people with concussion had not fully recovered six months after the injury. Our analysis showed that participants who had signs of greater thalamus connectivity in their brain very soon after injury were more likely to later develop post-concussive symptoms, such as fatigue and poor concentration.</p>
<h2>Concussion treatment</h2>
<p>Our research makes an important step in understanding concussion, showing that even a single brain injury can have clear consequences in some people. This damage may also not show up in the types of scans concussion patients are routinely given, suggesting it may be time to expand the types of imaging used. </p>
<p>We found that in people who experienced long-term symptoms, functional changes were still present in the brain 12 months after the injury. These effects were found in a sub-group who returned for scanning a year after their injury, and were not seen in patients without long-term symptoms. </p>
<p>Concussion is often viewed as a short-term event, but these findings suggest it can be a long-term disease, and some people may take longer to recover than others. </p>
<p>Our study also found that the long-term symptoms a person experiences may relate to different areas of the brain. We found that people who experienced long-term cognitive symptoms (such as concentration and memory problems) had increased connectivity from the thalamus to areas of the brain linked with noradrenaline – a chemical messenger in the brain. </p>
<p>Whereas people who experienced long-term emotional problems (such as depression or irritability) had greater connectivity to areas that produced a different chemical messenger, serotonin. </p>
<p>This not only shows us how concussion affects people differently, it may also give us targets we can use to develop drugs that alleviate concussion symptoms. </p>
<p>While concussion is considered a “mild” traumatic brain injury, our findings show it’s anything but – and can have long-term consequences for a large proportion of people. Although there’s still a lot we don’t know about concussion – including the effects that repetitive concussion may have on the brain – it’s promising to see this condition is being taken more seriously, especially in sports where it can be common. </p>
<p><a href="https://www.sportandrecreation.org.uk/policy/research-publications/concussion-guidelines">New UK guidelines</a> for grassroots sports like football and rugby now require players to sit out of play for at least 24 hours after a suspected concussion, which may help to prevent concussion and improve recovery after one.</p><img src="https://counter.theconversation.com/content/204702/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Woodrow receives funding from the Medical Research Council and the Pinsent Darwin Trust. </span></em></p><p class="fine-print"><em><span>David Menon receives research funding from the National Institute for Health Research, UK; UK Research and Innovation (UKRI); the Medical Research Council (UK); the Canadian Institute for Advanced Research (CIFAR); Addenbrooke's Charitable Trust; the Brain Research Trust (UK). He has consultancy or research collaboration agreements with NeuroTrauma Sciences LLC, Gryphon Inc, GlaxoSmithKline Ltd; Lantmannen AB; Pressure Neuro Ltd; Integra NeuroSciences Ltd; Cortirio Ltd; and Calico LLC.</span></em></p><p class="fine-print"><em><span>Emmanuel A Stamatakis receives funding from the Canadian Institute for Advanced Research and the Stephen Erskine Fellowship, Queens’ College, University of Cambridge.</span></em></p>Long-term symptoms of concussion can include trouble concentrating and emotional distress.Rebecca Woodrow, PhD Student in Clinical Neurosciences, University of CambridgeDavid Menon, Professor, Head of Division of Anaesthesia, University of CambridgeEmmanuel A Stamatakis, Lead, Cognition and Consciousness Imaging Group, Division of Anaesthesia, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2002272023-03-01T20:55:22Z2023-03-01T20:55:22ZCurious Kids: What happens to your brain if you don’t get enough sleep?<figure><img src="https://images.theconversation.com/files/512986/original/file-20230301-16-qnlajq.jpg?ixlib=rb-1.1.0&rect=0%2C511%2C5595%2C3476&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A common symptom of not getting enough quality sleep is ‘brain fog’ — when thoughts aren’t as clear and focused as they should be. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>Curious Kids is a series for children of all ages. Have a question you’d like an expert to answer? Send it to <a href="mailto:curiouskidscanada@theconversation.com">CuriousKidsCanada@theconversation.com</a>.</em></p>
<blockquote>
<p><strong>What happens to your brain if you don’t get enough sleep? — Avery, age 7, Napanee, Ont.</strong></p>
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<p>Sleep may be the single biggest factor in maintaining a <a href="https://doi.org/10.1002/da.22769">healthy brain and positive mental health</a>. This is especially true if you are under the age of 20. </p>
<p>What is interesting — and problematic — is that most of us live with a sleep debt: in essence we are not getting enough sleep, so we are <a href="https://www.cdc.gov/niosh/emres/longhourstraining/debt.html#">constantly sleep deprived</a>. And living with a sleep debt has a negative impact on brain function. </p>
<figure class="align-right ">
<img alt="A boy in pyjamas rubbing his eye, carrying a pillow" src="https://images.theconversation.com/files/512992/original/file-20230301-17-ak6abg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/512992/original/file-20230301-17-ak6abg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512992/original/file-20230301-17-ak6abg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512992/original/file-20230301-17-ak6abg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512992/original/file-20230301-17-ak6abg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512992/original/file-20230301-17-ak6abg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512992/original/file-20230301-17-ak6abg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Having a sleep debt can impair all of your brain’s systems — the ones that support perception, memory, attention, decision-making and even learning.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<p>One of the most common signs of having a sleep debt is <a href="https://www.healthline.com/health-news/foggy-brain-lack-of-sleep">feeling like you are in a brain fog</a>, where things are not as clear and focused as they should be. A lack of sleep can also make us more emotional and can contribute to depression. Further, having a sleep debt can impair all of your brain’s systems — the ones that support perception, memory, attention, decision-making and even learning. </p>
<p>As a neuroscientist, I am extremely interested in the factors that impact brain health and function. Research by my own laboratory, the <a href="http://www.krigolsonlab.com">Theoretical and Applied Neuroscience Laboratory</a> at the University of Victoria, demonstrated that sleep is the <a href="https://doi.org/10.3389/fnins.2021.634147">single biggest predictor of your brain’s ability to form new memories</a>.</p>
<h2>How much sleep do people need?</h2>
<p>You might wonder what a normal amount of sleep is or if you are getting enough sleep. Doctors and researchers recommend <a href="https://www.hopkinsmedicine.org/health/wellness-and-prevention/oversleeping-bad-for-your-health">between seven and nine hours of sleep per night for adults</a>. If you sleep more than that, it is worth talking with a doctor because oversleeping can be bad for you as well. </p>
<p>However, it is different for kids. Just after they are born, babies might need to sleep <a href="https://www.sleepfoundation.org/children-and-sleep/how-much-sleep-do-kids-need">up to 17 hours a day</a>, and they will not reach the seven-to-nine-hours range until the end of adolescence. School aged children (ages six to 12) typically need nine to 12 hours of sleep per night, and teenagers need between eight and 10 hours of sleep a night. </p>
<p>One interesting thing that science has shown us is that the circadian rhythm — our bodies’ natural clock cycle that determines when we sleep — <a href="https://www.sleepfoundation.org/teens-and-sleep">is different for teenagers than younger children and adults</a>. Teens’ desire to stay up late and sleep in is completely natural. </p>
<h2>How sleep works, and how it affects brain function</h2>
<p>Humans cycle through <a href="https://doi.org/10.1111/j.1749-6632.2009.04416.x">five different stages of sleep each night</a>: NREM1, NREM2, NREM3, NREM4 and REM sleep. </p>
<figure class="align-center ">
<img alt="Graph showing stages of sleep" src="https://images.theconversation.com/files/512972/original/file-20230301-1800-imzk9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512972/original/file-20230301-1800-imzk9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512972/original/file-20230301-1800-imzk9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512972/original/file-20230301-1800-imzk9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512972/original/file-20230301-1800-imzk9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512972/original/file-20230301-1800-imzk9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512972/original/file-20230301-1800-imzk9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">People cycle through the stages of sleep several times per night.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<p>REM stands for “rapid eye movement” and this is when we dream. NREM stands for “non rapid eye movement” and the stages are ranked from light sleep to deep sleep. Light — especially NREM2 — is a critical stage of sleep when memories form. NREM3 and NREM4 are crucial for your body to recover from injuries and to have energy for the next day. </p>
<p>In terms of how a lack of sleep impacts brain function, the most prominent working theory is that when we are sleep deprived, it reduces the ability of neurons — the cells that make up our brain — to communicate with each other. That means our brains do not function as effectively, which leads to <a href="https://doi.org/10.1007/s00018-007-6457-8">reduced brain function, poor brain health and potentially even mental health issues</a>. </p>
<h2>How to get quality sleep</h2>
<p>What can we do to improve the quality of our sleep and avoid having a sleep debt? First, try to go to bed at the same time every night and try waking up at the same time every day. A good metric of having good “sleep health” is the ability to wake up at close to the same time every day without needing an alarm clock. </p>
<figure class="align-center ">
<img alt="A child wearing glasses reading a book with a flashlight under a blanket" src="https://images.theconversation.com/files/512980/original/file-20230301-1750-251jxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512980/original/file-20230301-1750-251jxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512980/original/file-20230301-1750-251jxk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512980/original/file-20230301-1750-251jxk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512980/original/file-20230301-1750-251jxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512980/original/file-20230301-1750-251jxk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512980/original/file-20230301-1750-251jxk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">For quality sleep, avoid screens such as phones, tablets or televisions before bed.</span>
<span class="attribution"><span class="source">(Pexels/Kampus Production)</span></span>
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<p>It’s important to know that <a href="https://www.hopkinsmedicine.org/health/wellness-and-prevention/oversleeping-bad-for-your-health">you cannot oversleep to make up for a lack of sleep</a>. In fact, sleeping in on the weekend is one of the worst things you can do to recover from a sleep deficit. </p>
<p>Another thing you can do to improve the quality of your sleep is to avoid looking at screens — phones, computers, TVs — before you go to bed. The technology used to make these screens has been <a href="https://www.sleepfoundation.org/how-sleep-works/how-electronics-affect-sleep">shown to increase alertness, making it hard to fall asleep</a>. </p>
<p>Also, make sleep a priority — it is better to go to sleep and let your brain recover than it is to stay up late studying. In fact, one of the best things you can do at school to improve how well you learn is to get a good night’s sleep. </p>
<p>Finally, having a healthy, <a href="https://doi.org/10.1183/16000617.0110-2016">well-balanced diet and getting sufficient exercise</a> have also been shown to improve sleep health and sleep quality.</p>
<p>So make sure you get enough sleep. Not getting enough sleep is associated with reduced brain health and function, and can even lead to mental health problems such as anxiety and depression.</p><img src="https://counter.theconversation.com/content/200227/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Olave Krigolson receives funding from the Natural Sciences and Engineering Research Council of Canada.</span></em></p>We live in a world where we frequently do not get enough sleep, but we need sleep if our brains are going to stay healthy and function efficiently.Olave Krigolson, Professor, Neuroscience, University of VictoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1981092023-02-20T16:33:59Z2023-02-20T16:33:59ZHow your brain decides what to think<p>You’re sitting on the plane, staring out of the window at the clouds and all of a sudden, you think back to how a few months ago, you had a heart-to-heart with a good colleague about the pressure you experience at work. How do thoughts seemingly completely unrelated to the present pop into our heads? Why do we remember certain things and not others? Why does our mind go off on tangents and why do we have daydreams?</p>
<p>Underlying these processes is a shared pattern of common brain activity, in regions which together make up the “<a href="https://doi.org/10.1073/pnas.98.2.676">default mode network</a>”, discovered and named by neurologist Marcus Raichle in the early 2000s. It’s engaged when we are <a href="https://theconversation.com/explainer-why-daydreaming-is-good-for-you-50227">daydreaming</a>, thinking about ourselves or others, <a href="https://theconversation.com/daydream-believer-why-your-brain-is-wired-to-wander-18881">recalling memories, or imagining future events</a>.</p>
<p>The default mode network becomes engaged when people appear to be doing “nothing” (hence the term “default”). This is usually when we are in a relaxed state and not focusing on a task or goal – think, sitting on a plane, staring out the window.</p>
<p>When the default mode network is engaged, other networks in the brain are down-regulated or become less active, such as the executive control network and other brain regions involved in attention, working memory, and decision-making. This is what allows the brain to wander. </p>
<h2>Why some memories over others?</h2>
<p>Some memories are more likely to be spontaneously recalled, such as those that are more recent, highly emotional, highly detailed, frequently repeated, or central to our identity. They capture our attention – and for good reason. These types of memories were likely pivotal for engaging with our physical and social environments at the time, and so helped to contribute to our survival.</p>
<p>It’s thought that the brain stores memories in a reconstructive, associative way, <a href="https://www.britannica.com/topic/Remembering-A-Study-in-Experimental-and-Social-Psychology">storing memory details in a distributed manner</a> and bringing them together upon retrieval – rather than in a strictly reproductive way, with video replays of whole events stored in chronological order. </p>
<p>This means that memories may be associated with each other through different sensory, emotional and contextual details. So each of these bits of information can serve as a cue to trigger another memory. Such as when we encounter a smell, sound or image – even if we sometimes don’t consciously know what the trigger was.</p>
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<img alt="Woman sitting in bikini thinking." src="https://images.theconversation.com/files/508986/original/file-20230208-23-ov7tjc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/508986/original/file-20230208-23-ov7tjc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/508986/original/file-20230208-23-ov7tjc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/508986/original/file-20230208-23-ov7tjc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/508986/original/file-20230208-23-ov7tjc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/508986/original/file-20230208-23-ov7tjc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/508986/original/file-20230208-23-ov7tjc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">‘Why can’t I stop thinking about work?’</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/woman-sitting-on-armchair-under-white-patio-umbrella-1154638/">Pexels/Nappy</a></span>
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<p>Indeed, much of our cognitive processing happens <a href="https://theconversation.com/is-it-rational-to-trust-your-gut-feelings-a-neuroscientist-explains-95086">without conscious awareness</a>. The brain <a href="https://www.degruyter.com/document/doi/10.4159/9780674045217/html?lang=en">holistically and unconsciously</a> deals with all kinds of sensory information that comes in all at once. </p>
<p>As a result, it may feel like we are not in control of our thoughts, but much of this perceived control may be an illusion anyway. It might be that our consciousness is not in control of very much at all, but rather tries to explain and rationalise the <a href="https://doi.org/10.1037/0033-295X.84.3.231">unconscious cognitive processing</a> of our brains after the fact. </p>
<p>In other words, the brain is constantly processing information and making connections between different pieces of knowledge. This means that it’s normal for thoughts and associations to come to mind when our conscious control mechanisms are switched off.</p>
<h2>When thoughts turn bad</h2>
<p>The spontaneous nature of thoughts and memories brought up through the default mode network is what supports <a href="https://theconversation.com/the-secret-to-creativity-according-to-science-89592">imagination</a> and <a href="https://theconversation.com/new-study-reveals-why-some-people-are-more-creative-than-others-90065">creativity</a>. This is why we might have an “Aha!” moment in the shower and come up with a creative solution to a work problem we may have been stuck with. The brain was allowed to rest and wander, so it was able to make associations between different bits in memories that our conscious working memory was not able to reach and bring together. </p>
<p>Spontaneous thoughts are not always good, however. <a href="https://pubmed.ncbi.nlm.nih.gov/10087639/">Intrusive memories</a> are unwanted memories, that are often vivid and disturbing or at least strongly emotionally charged and can take the form of <a href="https://theconversation.com/the-possible-cause-of-flashbacks-discovered-59105">flashbacks</a> or <a href="https://theconversation.com/why-do-i-dwell-on-the-past-121630">ruminations</a>. Not only can they bring with them feelings of anxiety, fear and shame, but they can sometimes also consist of disturbing content that the person does not want to remember or think about. </p>
<figure class="align-center ">
<img alt="Woman with head in hands." src="https://images.theconversation.com/files/508988/original/file-20230208-16-aoiv10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/508988/original/file-20230208-16-aoiv10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/508988/original/file-20230208-16-aoiv10.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/508988/original/file-20230208-16-aoiv10.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/508988/original/file-20230208-16-aoiv10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/508988/original/file-20230208-16-aoiv10.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/508988/original/file-20230208-16-aoiv10.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Not all thoughts are welcome.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/faceless-unhappy-woman-covering-face-6383282/">Pexels/liza summer</a></span>
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<p>For example, in <a href="https://www.psychiatrist.com/jcp/mental/child/infant-related-intrusive-thoughts-of-harm/">postpartum anxiety and depression</a>, new mothers can start having intrusive thoughts of harming their infant, without actually wanting to follow through with them. This is understandably a highly disturbing experience and if it happens to you, please rest assured that such thoughts are unfortunately common. </p>
<p>But it’s always best to try and seek <a href="https://www.mind.org.uk/information-support/types-of-mental-health-problems/postnatal-depression-and-perinatal-mental-health/support-and-services/">help</a> or at least support at the earliest possible moment. <a href="https://www.ocduk.org/overcoming-ocd/cognitive-behavioural-therapy/">Cognitive behavioural therapy</a> (CBT) can help with techniques to deal with unwanted thoughts.</p>
<p>For all of us though, it’s worth remembering that many thoughts enter our minds seemingly spontaneously and that this is a normal part of human memory and thought processes. But by allowing ourselves and our brains to take a rest, we allow it to generate creative thoughts and solutions to problems. And when unwanted thoughts pop up, it might be best to take a mindful approach: observe the thought and let it go, like clouds in a passing storm.</p><img src="https://counter.theconversation.com/content/198109/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Valerie van Mulukom does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Spontaneous trips down memory lane: why and how the mind wanders.Valerie van Mulukom, Assistant Professor in Cognitive Science, Coventry UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1853602022-08-24T12:25:57Z2022-08-24T12:25:57ZDiet can influence mood, behavior and more – a neuroscientist explains<figure><img src="https://images.theconversation.com/files/478375/original/file-20220809-15110-gw5chs.jpg?ixlib=rb-1.1.0&rect=0%2C379%2C1200%2C1085&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">What we eat matters, and having just the right amount of essential nutrients is key to our overall health.</span> <span class="attribution"><a class="source" href="https://sites.lsa.umich.edu/dus-lab/ ">Niusha Shodja and Saina Heshmati, Storylab</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>During the long seafaring voyages of the 15th and 16th centuries, a period known as <a href="https://www.britannica.com/topic/European-exploration/The-Age-of-Discovery">the Age of Discovery</a>, sailors reported experiencing <a href="https://www.nationalgeographic.com/science/article/scurvy-disease-discovery-jonathan-lamb">visions of sublime foods and verdant fields</a>. The discovery that these were nothing more than hallucinations after months at sea was agonizing. Some sailors wept in longing; others threw themselves overboard. </p>
<p>The cure for these harrowing mirages turned out to be not a concoction of complex chemicals, as once suspected, but rather the simple antidote of lemon juice. These sailors <a href="https://www.nationalgeographic.com/science/article/scurvy-disease-discovery-jonathan-lamb">suffered from scurvy</a>, a disease caused by a deficiency of vitamin C, an essential micronutrient that people acquire from eating fruits and vegetables. </p>
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<p>Vitamin C is important <a href="https://doi.org/10.1186/s12888-020-02730-w">for the production and release of neurotransmitters</a>, the chemical messengers of the brain. In its absence, brain cells do not communicate effectively with one another, which can lead to hallucinations.</p>
<p>As this famous example of early explorers illustrates, there is an intimate connection between food and the brain, one that researchers like me are working to unravel. <a href="https://lsa.umich.edu/mcdb/people/faculty/mdus.html">As a scientist</a> <a href="https://scholar.google.com/citations?user=MbZxwzMAAAAJ&hl=en">who studies the neuroscience of nutrition</a> at the University of Michigan, I am primarily interested in how components of food and their breakdown products can alter the <a href="https://theconversation.com/what-you-eat-can-reprogram-your-genes-an-expert-explains-the-emerging-science-of-nutrigenomics-165867">genetic instructions that control our physiology</a>. </p>
<p>Beyond that, my research is also focused on understanding how food can <a href="https://www.bloomberg.com/news/videos/2022-05-12/can-a-different-diet-reprogram-your-dna-video">influence our thoughts, moods and behaviors</a>. While we can’t yet prevent or treat brain conditions with diet, researchers like me are learning a great deal about the role that nutrition plays in the everyday brain processes that make us who we are.</p>
<p>Perhaps not surprisingly, a delicate balance of nutrients is key for brain health: Deficiencies or excesses in vitamins, sugars, fats and amino acids can influence brain and behavior in either negative or positive ways. </p>
<h2>Vitamins and mineral deficiencies</h2>
<p>As with vitamin C, deficits in other vitamins and minerals can also precipitate nutritional diseases that adversely impact the brain in humans. For example, low dietary levels of vitamin B3/niacin – typically found in meat and fish – <a href="https://apps.who.int/iris/handle/10665/66704">cause pellagra</a>, a disease in which people develop dementia. </p>
<p>Niacin is essential to turn food into energy and building blocks, protect the genetic blueprint from environmental damage and control how much of certain gene products are made. In the absence of these critical processes, brain cells, also known as neurons, <a href="https://doi.org/10.3390%2Fijms20040974">malfunction and die prematurely</a>, leading to dementia. </p>
<p>In animal models, decreasing or blocking the production of niacin in the brain promotes neuronal damage and cell death. Conversely, enhancing niacin levels has been shown to mitigate the effects of neurodegenerative diseases such as <a href="https://doi.org/10.3390%2Fijms20040974">Alzheimer’s, Huntington’s and Parkinson’s</a>. Observational studies in humans suggest that sufficient levels of niacin <a href="https://doi.org/10.3390/ijms20040974">may protect against these diseases</a>, but the results are still inconclusive.</p>
<p>Interestingly, niacin deficiency caused by consumption of excessive amounts of alcohol can lead to similar effects as those found with pellagra.</p>
<p>Another example of how a nutrient deficiency affects brain function can be found in the element iodine, which, like niacin, must be acquired from one’s diet. Iodine, which is present in seafood and seaweed, is an essential building block for thyroid hormones – signaling molecules that are important for many aspects of human biology, including development, metabolism, appetite and sleep. Low iodine levels prevent the production of adequate amounts of thyroid hormones, impairing these essential physiological processes. </p>
<p>Iodine is particularly important to the developing human brain; before table salt was supplemented with this mineral in the 1920s, iodine deficiency was a <a href="https://web.archive.org/web/20060930020824/http://www.who.int/nutrition/topics/idd/en/">major cause of cognitive disability worldwide</a>. The introduction of iodized salt is thought to have contributed to the <a href="https://doi.org/10.1093%2Fjeea%2Fjvw002">gradual rise in IQ scores in the past century</a>.</p>
<h2>Ketogenic diet for epilepsy</h2>
<p>Not all dietary deficiencies are detrimental to the brain. In fact, studies show that people with drug-resistant epilepsy – a condition in which brain cells fire uncontrollably – <a href="https://doi.org/10.3390/nu12092645">can reduce the number of seizures</a> by adopting an ultralow-carbohydrate regimen, known as a <a href="https://nutrition.ucdavis.edu/outreach/nutr-health-info-sheets/pro-ketogenic-diet">ketogenic diet</a>, in which 80% to 90% of calories are obtained from fat. </p>
<p>Carbohydrates are the preferred energy source for the body. When they are not available – either because of fasting or because of a ketogenic diet – cells obtain fuel by breaking down fats into compounds called ketones. Utilization of ketones for energy leads to profound <a href="https://doi.org/10.1038/s41392-021-00831-w">shifts in metabolism and physiology</a>, including the levels of hormones circulating in the body, the amount of neurotransmitters produced by the brain and the types of bacteria living in the gut. </p>
<p>Researchers think that <a href="https://doi.org/10.1038/ejcn.2013.116">these diet-dependent changes</a>, especially the higher production of brain chemicals that can quiet down neurons and decrease levels of inflammatory molecules, may play a role in the ketogenic diet’s ability to lower the number of seizures. These changes may also explain the <a href="https://doi.org/10.15252%2Femmm.202114418">benefits of a ketogenic state</a> – either through diet or fasting – on cognitive function and mood. </p>
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<figcaption><span class="caption">Some foods can negatively affect your memory and mood.</span></figcaption>
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<h2>Sugar, saturated fats and ultraprocessed foods</h2>
<p>Excess levels of some nutrients can also have detrimental effects on the brain. In humans and animal models, elevated consumption of refined <a href="https://health.clevelandclinic.org/which-is-worse-for-you-fat-or-sugar/">sugars and saturated fats</a> – a combination commonly found in ultraprocessed foods – promotes eating by <a href="https://doi.org/10.3389/fnbeh.2021.746299">desensitizing</a> the brain to the hormonal signals known to regulate satiety. </p>
<p>Interestingly, a diet high in these foods also <a href="https://doi.org/10.1016%2Fj.tem.2020.11.011">desensitizes the taste system</a>, making animals and humans perceive food as less sweet. These sensory alterations may affect food choice as well as the reward we get from food. For example, research shows that people’s responses to ice cream in brain areas <a href="https://doi.org/10.3945/ajcn.111.027003">important for taste and reward</a> are dulled when they eat it every day for two weeks. Some researchers think this decrease in food reward signals may <a href="https://theconversation.com/foods-high-in-added-fats-and-refined-carbs-are-like-cigarettes-addictive-and-unhealthy-165441">enhance cravings for even more fatty and sugary foods</a>, similar to the way smokers crave cigarettes. </p>
<p>High-fat and processed-food diets are also associated with lower cognitive function and memory <a href="https://doi.org/10.3389%2Ffnbeh.2021.746299">in humans</a> and <a href="https://doi.org/10.3389%2Ffnbeh.2021.746299">animal models</a> as well as a higher incidence of neurodegenerative diseases. However, researchers still don’t know if these effects are due to these foods or to the weight gain and insulin resistance that <a href="https://doi.org/10.3389/fnbeh.2021.746299">develop with long-term consumption of these diets</a>.</p>
<h2>Time scales</h2>
<p>This brings us to a critical aspect of the effect of diet on the brain: time. Some foods can influence brain function and behavior acutely – such as over hours or days – while others take weeks, months or even years to have an effect. For instance, eating a slice of cake rapidly shifts the fat-burning, ketogenic metabolism of an individual with drug-resistant epilepsy into a carbohydrate-burning metabolism, increasing the risk of seizures. In contrast, it takes weeks of sugar consumption for taste and the brain’s reward pathways to change, and months of vitamin C deficiency to develop scurvy. Finally, when it comes to diseases like Alzheimer’s and Parkinson’s, risk is influenced by years of dietary exposures in combination with other genetic or <a href="https://cshperspectives.cshlp.org/content/10/4/a033118.long">lifestyle factors such as smoking</a>.</p>
<p>In the end, the relationship between food and the brain is a bit like the delicate Goldilocks: We need not too little, not too much but just enough of each nutrient.</p><img src="https://counter.theconversation.com/content/185360/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Dus receives funding from the National Science Foundation, the National Institute of Health, the Sloan Foundation, the Rita Allen Foundation, and the Klingenstein Foundation. She is affiliated with The University of Michigan, Ann Arbor. She is on the Advisory Board for the Trends in Endocrinology & Metabolism journal, the Editorial Board for the Chemical Senses journal, and the Advisory Board for the University of Michigan Museum of Natural History.</span></em></p>Diets high in fat, sugar and processed foods are associated with higher calorie intake, poorer memory and lower cognitive function.Monica Dus, Associate Professor of Molecular, Cellular, and Developmental Biology, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1840352022-06-21T11:48:59Z2022-06-21T11:48:59ZKids’ neighborhoods can affect their developing brains, a new study finds<figure><img src="https://images.theconversation.com/files/467784/original/file-20220608-25-sm6gka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Children living in low-income neighborhoods with 'hands-off' norms about safety showed higher levels of reactivity in a region of the brain associated with emotion processing and threat detection.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/poor-neighborhood-royalty-free-image/172857417?adppopup=true">DenisTangneyJr/E+ via Getty Images</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em> </p>
<h2>The big idea</h2>
<p>Children growing up in more disadvantaged neighborhoods – meaning those with poor housing quality, more poverty and lower levels of employment and education – show observable increases in brain activity when viewing emotional faces on a screen, according to <a href="https://doi.org/10.1016/j.dcn.2022.101061">our team’s new study</a>. But importantly, we found that this association was true only when the adults in those neighborhoods also did not have strong shared norms about preventing crime and violence.</p>
<p>Our findings emphasize that where children live and the resources of others in the neighborhood may affect brain development. But neighbors may help protect children from these effects on the brain when they are able to build positive social norms about looking out for one another and preventing violence.</p>
<p>To get at these findings, we recruited families from neighborhoods in southern Michigan with above-average levels of disadvantage. We used functional magnetic resonance imaging, or fMRI, to measure adolescents’ brain activity while they looked at facial expressions of different emotions. We focused on observing brain activity in the amygdala, a region of the brain <a href="https://doi.org/10.1023/A:1025048802629">responsible for detecting threats and processing emotions</a>. </p>
<p>We used <a href="https://www.neighborhoodatlas.medicine.wisc.edu/">neighborhood census data</a> on factors such as home ownership rates, percentage of families living below the poverty line and percent unemployed to measure neighborhood disadvantage. We then asked randomly selected neighbors of each family to answer questions about the social norms within their neighborhoods, especially regarding shared beliefs about crime and violence prevention. </p>
<p>We found that youth ages 7 to 19 who lived in neighborhoods with more disadvantage had greater reactivity in the amygdala to fearful and angry faces. But neighbors who shared strong social norms, such as believing that adults should do something if children are fighting, seemed to offset this effect. That is, neighborhood disadvantage was related to amygdala reactivity only when neighbors had more hands-off attitudes about preventing violence. </p>
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<figcaption><span class="caption">Family engagement strengthens not only the family but also the health of the community, which in turn can have beneficial effects on child development.</span></figcaption>
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<h2>Why it matters</h2>
<p>In 2020, <a href="https://datacenter.kidscount.org/data/tables/6795-children-living-in-high-poverty-areas?loc=1&loct=1">approximately 6.4 million children</a> in the U.S. were living in neighborhoods with poverty rates of 30% or more. Studies show that youths growing up in more impoverished neighborhoods are more likely to perform <a href="https://doi.org/10.1037/0033-2909.126.2.309">worse in school and have greater mental health problems</a>. </p>
<p>Disadvantaged neighborhoods <a href="https://doi.org/10.1037/0003-066X.59.2.77">introduce higher risks for children</a> that go beyond a family’s own resources or environment. This is because these neighborhoods increase children’s exposure to violent crime and physical hazards such as pollution, toxicants and street traffic, and they decrease access to healthy food options and high-quality schools. </p>
<p>Our research, alongside <a href="https://doi.org/10.1111/cdep.12453">other recent studies</a>, highlights that neighborhood disadvantage can get “under the skin.” In other words, it can affect child development by shaping brain structure and function, in addition to affecting other systems of the body, <a href="https://doi.org/10.3389/fnhum.2012.00277">like the stress response system</a>. </p>
<p>Unfortunately, studies show that such <a href="https://doi.org/10.1146/annurev.soc.28.110601.141114">structural factors</a> as where freeways are built and how neighborhood boundaries are defined can concentrate disadvantage <a href="https://doi.org/10.1001/jamapediatrics.2021.3594">into specific neighborhoods</a>. This, in turn, makes it harder for <a href="https://doi.org/10.1126/science.277.5328.918">neighbors to build strong relationships and norms</a>. So although neighbors can work to promote a more positive environment for children, <a href="https://nap.nationalacademies.org/child-poverty/highlights.html">policy level changes</a> may be needed to help neighbors and families thrive in more disadvantaged neighborhoods. </p>
<h2>What other research is being done</h2>
<p>Recent studies from other researchers have been trying to understand why living in a disadvantaged neighborhood affects brain development and to identify additional factors that may protect children.</p>
<p>For example, in a peer-reviewed study that is not yet published, researchers found that <a href="https://psyarxiv.com/k37rf/">deadly gun violence</a> within a half-mile of children’s houses was related to the communication between brain regions important for emotion processing and self-regulation. And, like our study, they found that this effect was offset by positive neighborhood relationships. </p>
<p>Other work shows that <a href="https://doi.org/10.1016/j.neuroimage.2016.01.036">exposure to air pollution</a> from car traffic is associated with differences in how children’s brains develop.</p><img src="https://counter.theconversation.com/content/184035/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gabriela Suarez receives funding from the National Science Foundation Graduate Research Fellowship and a supplement from the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health. </span></em></p>The latest findings add to the understanding of how social disadvantage such as poverty and low-quality, unsafe housing can affect early child development.Gabriela Suarez, PhD Candidate in Developmental Psychology, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1809452022-05-05T12:42:27Z2022-05-05T12:42:27ZYou’ve likely heard of the brain’s gray matter – here’s why the white matter is important too<figure><img src="https://images.theconversation.com/files/458358/original/file-20220415-24-rq7g23.jpg?ixlib=rb-1.1.0&rect=0%2C14%2C5000%2C3712&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The brain's neural network, which includes both gray and white matter.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/brain-neural-network-royalty-free-illustration/460711949?adppopup=true">Pasieka/Science Photo Library via Getty Images</a></span></figcaption></figure><p>Who has not contemplated how a memory is formed, a sentence generated, a sunset appreciated, a creative act performed or a heinous crime committed?</p>
<p>The human brain is a three-pound organ that remains largely an enigma. But most people have heard of the brain’s <a href="https://pubmed.ncbi.nlm.nih.gov/31990494/">gray matter</a>, which is needed for cognitive functions such as learning, remembering and reasoning. </p>
<p>More specifically, gray matter refers to regions throughout the brain where nerve cells – <a href="https://www.ninds.nih.gov/health-information/patient-caregiver-education/brain-basics-life-and-death-neuron#">known as neurons</a> – are concentrated. The region considered most important for cognition is <a href="https://www.ninds.nih.gov/health-information/patient-caregiver-education/brain-basics-know-your-brain#The%20Cerebral%20Cortex">the cerebral cortex</a>, a thin layer of gray matter on the brain’s surface. </p>
<p>But the other half of the brain – <a href="https://www.medicalnewstoday.com/articles/318966#Viewing-white-matter">the white matter</a> – is often overlooked. White matter lies below the cortex and also deeper in the brain. Wherever it is found, white matter connects neurons within the gray matter to each other.</p>
<p>I am a <a href="https://medschool.cuanschutz.edu/alzheimer/about/directory/faculty/christopher-filley">professor of neurology and psychiatry</a> and the director of the behavioral neurology section at the University of Colorado Medical School. My work involves the evaluation, treatment and investigation of older adults with dementia and younger people with traumatic brain injury.</p>
<p>Finding out how these disorders affect the brain has motivated many years of my study. I believe that understanding white matter is perhaps a key to understanding these disorders. But so far, researchers have generally not given white matter the attention it deserves.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/461121/original/file-20220503-50169-zdtzie.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An illustration showing how neurons in the human brain connect to each other via the axons, which are surrounded by the myelin sheath." src="https://images.theconversation.com/files/461121/original/file-20220503-50169-zdtzie.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461121/original/file-20220503-50169-zdtzie.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461121/original/file-20220503-50169-zdtzie.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461121/original/file-20220503-50169-zdtzie.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461121/original/file-20220503-50169-zdtzie.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=492&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461121/original/file-20220503-50169-zdtzie.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=492&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461121/original/file-20220503-50169-zdtzie.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=492&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The approximately 100 billion neurons in the human brain are connected to each other by axons, many of which are surrounded by the myelin sheath. These axons, together with their myelin, make up the white matter, which helps facilitate communication between neurons throughout the brain.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/neuron-nerve-cell-body-in-orange-is-represented-with-its-news-photo/179798658?adppopup=true">BSIP/Universal Images Group via Getty Images</a></span>
</figcaption>
</figure>
<h2>Figuring out the white matter</h2>
<p>This lack of recognition largely stems from the difficulty in studying white matter. Because it’s located below the surface of the brain, even the most high-tech imaging can’t easily resolve its details. But recent findings, made possible by advancements in brain imaging and autopsy examinations, are beginning to show researchers how critical white matter is.</p>
<p>White matter is comprised of many <a href="https://qbi.uq.edu.au/brain/brain-anatomy/axons-cable-transmission-neurons">billions of axons</a>, which are like long cables that carry electrical signals. Think of them as elongated tails that act as extensions of the neurons. The axons connect neurons to each other at junctions called synapses. That is where communication between neurons takes place. </p>
<p>Axons come together in bundles, or tracts, that course throughout the brain. Placed end to end, their combined length in a single human brain is approximately 85,000 miles. Many axons are <a href="https://www.brainfacts.org/brain-anatomy-and-function/anatomy/2015/myelin">insulated with myelin</a>, a layer of mostly fat that speeds up electrical signaling, or communication, between neurons by up to 100 times. </p>
<p>This increased speed is crucial for <a href="https://www.nbia.ca/brain-structure-function/">all brain functions</a> and is partly why Homo sapiens have unique mental capacities. While there’s no doubt <a href="https://www.quantamagazine.org/how-humans-evolved-supersize-brains-20151110/#">our large brains</a> are due to evolution’s addition of neurons over eons, there has been an even greater <a href="https://doi.org/10.1073/pnas.090504197">increase in white matter</a> over evolutionary time. </p>
<p>This little-known fact has profound implications. The increased volume of white matter – mainly from the myelin sheaths that surround axons – enhances the efficiency of neurons in the gray matter to optimize brain function.</p>
<p>Imagine a nation of cities that are all functioning independently, but not linked to other cities by roads, wires, the internet or any other connections. This scenario would be analogous to the brain without white matter. Higher functions like language and memory are organized into networks in which gray matter regions are connected by white matter tracts. The more extensive and efficient those connections, the better the brain works.</p>
<h2>White matter and Alzheimer’s</h2>
<p>Given its essential role in the connections between brain cells, <a href="https://doi.org/10.1196/annals.1444.017">damaged white matter</a> can disturb any aspect of cognitive or emotional function. White matter pathology is present in many brain disorders and can be severe enough <a href="https://doi.org/10.1196/annals.1444.017">to cause dementia</a>. Damage to myelin is common in these disorders, and when the disease or injury is more severe, axons can also be damaged.</p>
<p>More than 30 years ago, my colleagues and I described this syndrome as <a href="https://medschool.cuanschutz.edu/docs/librariesprovider61/publications/wmd-paper-nnbn-1988_web.pdf?sfvrsn=435286ba_2">white matter dementia</a>. In this condition, the dysfunctional white matter is no longer adequately performing as a connector, meaning that the gray matter cannot act together in a seamless and synchronous manner. The brain, in essence, has been disconnected from itself. </p>
<p>Equally important is the possibility that white matter dysfunction plays a role in many diseases currently thought to originate in gray matter. Some of these diseases stubbornly defy understanding. For example, I suspect white matter damage may be critical in the early phases of Alzheimer’s disease and traumatic brain injury. </p>
<p>Alzheimer’s is the <a href="https://www.webmd.com/alzheimers/guide/alzheimers-dementia">most common type of dementia in older individuals</a>. It can impair cognitive function and rob people of their very identity. No cure or effective treatment exists. Ever since <a href="https://doi.org/10.1002/ca.980080612">Alois Alzheimer’s 1907 observations</a> of gray matter proteins – called amyloid and tau – neuroscientists have believed the buildup of these proteins <a href="https://doi.org/10.1056/NEJMra0909142">is the central problem</a> behind Alzheimer’s. Yet many drugs that remove these proteins <a href="https://doi.org/10.1080/21507740.2021.1941402">do not stop</a> <a href="https://theconversation.com/the-fda-approved-a-new-drug-to-treat-alzheimers-but-medicare-wont-always-pay-for-it-a-doctor-explains-what-researchers-know-about-biogens-aduhelm-179177">the patients’ cognitive decline</a>. </p>
<p><a href="https://doi.org/10.1093/braincomms/fcaa132">Recent findings increasingly suggest</a> that white matter damage – preceding the accumulation of those proteins – <a href="https://doi.org/10.1093/braincomms/fcaa132">may be the true culprit</a>. As brains age, they often experience gradual loss of blood flow from the narrowing of vessels that convey blood from the heart. Lower blood flow heavily impacts white matter. </p>
<p>Remarkably, there is even evidence that inherited forms of Alzheimer’s also feature <a href="https://doi.org/10.1002/ana.24647">early white matter abnormalities</a>. That means therapies aimed at maintaining blood flow to white matter may prove more effective than attempting to dislodge proteins. One simple treatment likely to help is <a href="https://doi.org/10.1001/jama.2019.10551">controlling high blood pressure</a>, as this can reduce the severity of white matter abnormalities. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/lNdRtTTbLDM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">From Loma Linda University Health: New discoveries to help the millions with traumatic brain injuries.</span></figcaption>
</figure>
<h2>White matter and traumatic brain injury</h2>
<p>Patients with traumatic brain injury, particularly those with moderate or severe injuries, can have lifelong disability. One of the most ominous outcomes of TBI is <a href="https://doi.org/10.1097/NEN.0b013e3181a9d503">chronic traumatic encephalopathy</a>, a brain disease believed to cause progressive and irreversible dementia. In TBI patients, the accumulation of tau protein in gray matter is evident. </p>
<p>Researchers have long recognized that white matter damage is common in people who have sustained a TBI. <a href="https://doi.org/10.1212/WNL.0000000000013012">Observations from the brains</a> of those with repetitive traumatic brain injuries – football players and military veterans have been frequently studied – have shown that white matter damage is prominent, and may precede the appearance of tangled proteins in the gray matter. </p>
<p>Among scientists, there is a burgeoning excitement over the <a href="https://doi.org/10.1007/s11357-021-00461-8">new interest in white matter</a>. Researchers are now beginning to acknowledge that the traditional focus on the study of gray matter has not produced the results they hoped. Learning more about the half of the brain known as white matter may help us in the years ahead to find the answers needed to alleviate the suffering of millions. </p>
<p>[<em>Get more science, health and technology news.</em> <a href="https://memberservices.theconversation.com/newsletters/?nl=science&source=inline-science-fascinating">Sign up for The Conversation’s weekly science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/180945/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher M. Filley receives funding from the Marcus Institute for Brain Health at the University of Colorado, and the U.S. Department of Defense, In the past he has received funding from the U.S. National Institutes of Health.</span></em></p>Long overlooked by scientists, white matter may provide clues to some of the brain’s greatest mysteries.Christopher M. Filley, Professor of Neurology and Psychiatry, University of Colorado Anschutz Medical CampusLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1772442022-03-13T12:28:41Z2022-03-13T12:28:41ZWhen you eat matters: How your eating rhythms impact your mental health<figure><img src="https://images.theconversation.com/files/450784/original/file-20220308-3342-10y3ywk.jpg?ixlib=rb-1.1.0&rect=1146%2C204%2C5333%2C3390&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When the main circadian clock in the brain is out of sync with eating rhythms, it impacts the brain's ability to function fully.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Eating is an essential part of human life and it turns out that not only what we eat but when we eat can impact our brains. Irregular eating times have been shown to contribute to poor mental health, including depression and anxiety, as well as to <a href="https://dx.doi.org/10.3390%2Fnu13082775">cardio-metabolic diseases and weight gain</a>. </p>
<p>Fortunately, it is possible to <a href="https://dx.doi.org/10.1038%2Fs41398-020-0694-0">leverage our eating rhythms</a> to limit negative mood and increase mental health. As a doctoral student in the field of neuropsychiatry and a psychiatrist studying nutrition and mood disorders, our research focuses on investigating how eating rhythms impact the brain. </p>
<p>Here’s how it all works: The circadian clock system is responsible for aligning our internal processes at optimal times of day based on cues from the environment such as light or food. Humans have evolved this wiring to meet energy needs that change a lot throughout the day and night, creating a rhythmic pattern to our eating habits that follows the schedule of the sun. </p>
<p>Although the main clock manages metabolic function over the day-night cycle, our eating rhythms also impact the main clock. Digestive tissues have their own clocks and show regular oscillations in functioning over the 24-hour cycle. For example, the small intestine and liver <a href="https://dx.doi.org/10.3389%2Ffnut.2020.00018">vary throughout the day and night in terms of digestive, absorptive and metabolic capacity</a>.</p>
<p>When the main circadian clock in the brain is out of sync with eating rhythms, it impacts the brain’s ability to function fully. Even though the brain is only two per cent of our total body mass, it consumes up to 25 per cent of our energy and is particularly <a href="https://dx.doi.org/10.1016%2Fj.tins.2013.07.001">affected by changes in calorie intake</a>. This means that abnormal meal times are bound to have negative health outcomes. </p>
<h2>Food and mood</h2>
<p>Although the underlying mechanisms are still unknown, there is overlap between neural circuits governing eating and mood. Also, digestive hormones exert effects on dopamine, a neurotransmitter that plays a large role in mood, energy and pleasure. Individuals with <a href="https://dx.doi.org/10.1073%2Fpnas.1500877112">depression and bipolar disorder have abnormal dopamine levels</a>. Altered eating rhythms are thought to contribute to the poor maintenance of mood. </p>
<figure class="align-center ">
<img alt="A chalk drawing of a brain on a blackboard, with the right half of the brain filled in with healthy foods" src="https://images.theconversation.com/files/450786/original/file-20220308-23-10zpba4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450786/original/file-20220308-23-10zpba4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=278&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450786/original/file-20220308-23-10zpba4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=278&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450786/original/file-20220308-23-10zpba4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=278&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450786/original/file-20220308-23-10zpba4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=349&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450786/original/file-20220308-23-10zpba4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=349&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450786/original/file-20220308-23-10zpba4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=349&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">There is overlap between the neural circuits governing eating and mood.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Irregular eating may even play a role in the complex underlying causes of mood disorders. For example, individuals with depression or bipolar disorder <a href="https://doi.org/10.1016/j.jpsychires.2009.08.003">exhibit disturbed internal rhythms and irregular meal times</a>, which significantly worsen mood symptoms. In addition, shift workers — who tend to have irregular eating schedules — <a href="https://dx.doi.org/10.2105%2FAJPH.2019.305278">demonstrate increased rates of depression and anxiety</a> when compared to the general population. Despite this evidence, assessing eating rhythms is not currently part of standard clinical care in most psychiatric settings. </p>
<h2>Optimizing eating rhythms</h2>
<p>So, what can be done to optimize our eating rhythms? One promising method we have encountered in our research is time-restricted eating (TRE), also known as intermittent fasting. </p>
<p>TRE involves restricting the eating window to a certain amount of time during the day, <a href="https://doi.org/10.1016/j.cmet.2016.06.001">typically four to 12 hours</a>. For example, choosing to eat all meals and snacks in a 10-hour window from 9:00 a.m. to 7:00 p.m. reflects an overnight fasting period. Evidence suggests that this method optimizes brain function, energy metabolism and the healthy signalling of metabolic hormones. </p>
<p>TRE has already been shown to <a href="https://doi.org/10.1002/jnr.24741">prevent depressive and anxiety symptoms in animal studies designed to model shift work</a>. The antidepressant effects of TRE <a href="https://dx.doi.org/10.2174%2F1570159X13666150326003852">have also been shown in humans</a>. Eating on a regular schedule is also beneficial to reduce the <a href="https://dx.doi.org/10.1038%2Fnm.3010">risk of health issues such as obesity, diabetes and cardiovascular disease</a>.</p>
<h2>Circadian rhythms in a 24-hour world</h2>
<p>We live in a 24-hour world filled with artificial light and round-the-clock access to food. That makes the effects of disturbed eating rhythms on mental health an important topic for modern life. As more research provides data assessing eating rhythms in individuals with mood disorders, incorporating eating rhythm treatment into clinical care could significantly improve patient quality of life. </p>
<p>For the general population, it is important to increase public knowledge on accessible and affordable ways to maintain healthy eating. This includes paying attention not only to the content of meals but also to eating rhythms. Aligning eating rhythms with the schedule of the sun will have lasting benefits for general well-being and may have a protective effect against mental illness.</p><img src="https://counter.theconversation.com/content/177244/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elisa Brietzke receives funding from Faculty of Health Sciences, Department of Psychiatry and Centre for Neuroscience Studies (CNS), Queen's University.</span></em></p><p class="fine-print"><em><span>Elena Koning does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Healthy eating is not just what you eat, but when you eat. Eating rhythms that are in sync with the circadian clock can benefit general well-being and may have a protective effect against mental illness.Elena Koning, PhD Student, Centre for Neuroscience Studies, Queen's University, OntarioElisa Brietzke, Professor, Department of Psychiatry, Queen's University, OntarioLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1742222022-01-26T19:58:40Z2022-01-26T19:58:40ZConcussion management is changing as more research suggests exercise is best approach<figure><img src="https://images.theconversation.com/files/442339/original/file-20220124-27-rrhb4u.jpg?ixlib=rb-1.1.0&rect=208%2C6%2C3525%2C2146&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Concussion patients were once prescribed rest in a dark room, but in recent years concussion management has literally come out of the dark.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 175px; border: none; position: relative; z-index: 1;" allowtransparency="" src="https://narrations.ad-auris.com/widget/the-conversation-canada/concussion-management-is-changing-as-more-research-suggests-exercise-is-best-approach" width="100%" height="400"></iframe>
<p><a href="http://doi.org/10.1212/01.wnl.0000801820.38637.38">Public interest in concussion has exploded over the space of a generation</a>, together with a new understanding of how best to help patients recover. Concussion patients were once prescribed rest in a dark room, but in recent years concussion management has literally come out of the dark.</p>
<p>This is in large part because of a research boom: the number of studies on this mild form of traumatic brain injury has <a href="https://pubmed.ncbi.nlm.nih.gov/?term=concussion&timeline=expanded">multiplied by 15 times over the last 20 years</a>. This spike is a sign that the relatively young field of concussion research is maturing into a deeper science. It has created new evidence to support an entirely new approach to treating concussion. A recent wave of research papers has turned old practices on their heads.</p>
<h2>Past approach: A dark room</h2>
<p>For many years, concussion management followed a <a href="http://doi.org/10.1001/jamaneurol.2018.0006">rest-is-best</a> approach.</p>
<p>Under this passive approach, patients were advised to avoid cognitive and physical activity until their symptoms naturally resolved, leading to the notion that a dark room was the best environment for recovery.</p>
<figure class="align-center ">
<img alt="Two soccer players colliding while trying to head a ball" src="https://images.theconversation.com/files/442147/original/file-20220124-27-15ph81j.jpg?ixlib=rb-1.1.0&rect=182%2C0%2C3771%2C2795&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/442147/original/file-20220124-27-15ph81j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442147/original/file-20220124-27-15ph81j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442147/original/file-20220124-27-15ph81j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442147/original/file-20220124-27-15ph81j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442147/original/file-20220124-27-15ph81j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442147/original/file-20220124-27-15ph81j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The number of research papers on concussion management has increased greatly over the last 20 years, leading to new approaches to treatment.</span>
<span class="attribution"><span class="source">(AP Photo/Phelan M. Ebenhack)</span></span>
</figcaption>
</figure>
<p>The problem was that there was scant evidence to support the dark-room method.</p>
<p>The motivation for using rest as a concussion-management strategy was a desire to <a href="https://doi.org/10.3928/00904481-20120827-12">limit exposure to environments and activities that might lead to secondary concussions</a>, which can have compounding, longer-lasting effects. Avoiding secondary injury was prioritized over proactive recovery.</p>
<p>But we are now in the midst of a transformation in concussion management.</p>
<h2>Exercise is medicine</h2>
<p>In the past few years, scientists have started to study aerobic exercise (or cardio training) as a management strategy for concussion symptoms. This <a href="http://doi.org/10.1249/JSR.0000000000000505">exercise-is-medicine</a> approach is diametrically opposed to the rest-is-best status quo.</p>
<p><a href="https://doi.org/10.1249/mss.0000000000002663">Many studies</a> have examined the effects of sub-maximal (low-to-moderate intensity) aerobic exercise on concussion symptoms. This research confirms the utility and safety of such exercise for managing concussion symptoms, which vary between individuals, but they are typically categorized as <a href="http://dx.doi.org/10.1136/bjsports-2017-097699">somatic (or physical), cognitive, emotional and sleep-related</a>. They can be assessed using adult- and child-specific symptom scales.</p>
<figure class="align-center ">
<img alt="A man running on a treadmill while another man wearing a lanyard observes." src="https://images.theconversation.com/files/442573/original/file-20220125-19-11lqfs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/442573/original/file-20220125-19-11lqfs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442573/original/file-20220125-19-11lqfs9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442573/original/file-20220125-19-11lqfs9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442573/original/file-20220125-19-11lqfs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442573/original/file-20220125-19-11lqfs9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442573/original/file-20220125-19-11lqfs9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Prescribing exercise in concussion typically involves a baseline test.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p><a href="http://doi.org/10.1249/MSS.0000000000002663">An academic review</a> that summarizes the findings of individual studies shows that exercise is indeed one of the most effective, evidence-informed strategies for managing concussion symptoms. Beyond a brief period (24 to 48 hours) of rest after concussion, the science now suggests that exercise is more beneficial than rest.</p>
<p>Prescribing exercise in concussion typically involves a baseline test. The most widely studied tests require patients either to walk on a treadmill with the incline gradually increasing throughout the test or cycle on a stationary bicycle against progressively increasing resistance. </p>
<p>Patients exercise under supervision until they experience an increase in symptoms (<a href="https://doi.org/10.1097/JSM.0000000000000431">which research shows is transient and not associated with poor long-term outcome</a>) or are unable to continue exercising. The heart rate at the point where the test is terminated is noted, and patients are then prescribed an exercise program involving five to six days of aerobic exercise at an intensity equivalent to 80 per cent of the maximum heart rate achieved during the test.</p>
<h2>Ongoing research</h2>
<figure class="align-center ">
<img alt="Man sitting on grass with his eyes closed and his fingertips on his temples" src="https://images.theconversation.com/files/442160/original/file-20220124-13-dseuqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/442160/original/file-20220124-13-dseuqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442160/original/file-20220124-13-dseuqc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442160/original/file-20220124-13-dseuqc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442160/original/file-20220124-13-dseuqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442160/original/file-20220124-13-dseuqc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442160/original/file-20220124-13-dseuqc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The motivation for using rest as a concussion-management strategy was a desire to limit exposure to environments and activities that might lead to secondary concussions.</span>
<span class="attribution"><span class="source">(Pexels/Kindel Media)</span></span>
</figcaption>
</figure>
<p>As a next step, scientists are hard at work trying to determine the exact mechanism by which such sub-maximal exercise improves concussion symptoms. <a href="https://doi.org/10.3233/NRE-172298">A leading hypothesis</a> is that the autonomic nervous system (which regulates involuntary physiological processes, such as heart rate and breathing) is disturbed following a concussion, with its two constituent sub-systems becoming “uncoupled.”</p>
<p>Sub-maximal aerobic exercise is thought to engage the autonomic nervous system in a way that helps restore balance to this critical command centre. Simply put, it looks like exercise can safely and effectively generate the biological change required to overcome the symptoms of concussion.</p>
<p>More research is needed to build on this growing base of exercise-concussion knowledge. We need to understand how different frequencies, intensities, times and types of exercise can lessen symptom burden.</p>
<figure class="align-right ">
<img alt="Illustration of a brain on a purple and blue background" src="https://images.theconversation.com/files/442165/original/file-20220124-21-1wbjqdr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/442165/original/file-20220124-21-1wbjqdr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=456&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442165/original/file-20220124-21-1wbjqdr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=456&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442165/original/file-20220124-21-1wbjqdr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=456&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442165/original/file-20220124-21-1wbjqdr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=573&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442165/original/file-20220124-21-1wbjqdr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=573&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442165/original/file-20220124-21-1wbjqdr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=573&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Researchers need to know how exercise impacts brain function in concussion as.</span>
<span class="attribution"><span class="source">(Unsplash/Fakurian Design)</span></span>
</figcaption>
</figure>
<p>Other research, including my ongoing work at McMaster University, aims to develop understanding of the effects of exercise by studying its impacts not only on symptoms, but also on brain activity. We need to know how exercise impacts brain function in concussion as, after all, concussions are brain injuries.</p>
<p>This shift in concussion management may mean better care will become available for patients. It is also a story about the power of bold science, the type of science which questions accepted wisdom and rebuilds first principles using evidence.</p>
<p>Challenging norms by changing perspective can lead to new approaches and better outcomes. Sometimes, as in the case with concussion, the game needs to be changed.</p><img src="https://counter.theconversation.com/content/174222/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bhanu Sharma receives funding from the Canadian Institutes of Health Research. </span></em></p>For many years, concussion treatment followed a rest-is-best approach. But research now suggests that low-to-moderate intensity exercise is a safe and useful approach to managing concussion symptoms.Bhanu Sharma, Post Doctoral Fellow, Faculty of Engineering, McMaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1511432021-01-07T19:09:31Z2021-01-07T19:09:31ZPhysical activity is good for your concentration – here’s why<figure><img src="https://images.theconversation.com/files/374811/original/file-20201214-23-12333ej.jpg?ixlib=rb-1.1.0&rect=11%2C5%2C3982%2C2652&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Even short periods of physical activity can improve concentration throughout the day.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/asian-boys-girls-fitness-outdoor-concept-1661190802">Somkid Saowaros/ Shutterstock</a></span></figcaption></figure><p>Whether it’s during the post-lunch slump or just one of those days, we all struggle to concentrate on what we’re doing sometimes, whether that’s at work, school, or home. Being able to concentrate on what we’re doing would inevitably make us more productive, but that’s often easier said than done. For people looking to improve their concentration, exercise is often recommended as the antidote – and for good reason, as research shows that physical activity can improve concentration in people of all ages.</p>
<p>I’ll define “concentration” as our ability to focus on a task and ignore distractions. So in order to have good concentration, we need to have two important aspects of cognitive function working at their best. The first is sustained attention, in which we’re able to focus on certain pieces of information for prolonged periods of time. The second is executive function, which is our ability to think and make decisions at a complex level.</p>
<p>But how does exercise help us improve these skills? Most research into the effects of exercise on concentration have studied the links in young people in schools. This is likely because of the clear effect concentration has on academic achievement, with a key priority of schools being to improve academic achievement and exam results. </p>
<p>Research shows that acute bouts of physical activity (such as walking or running during break) have a positive effect on concentration in young people. This effect has been shown after various forms of physical activity including <a href="https://www.sciencedirect.com/science/article/pii/S0306452209001171?casa_token=37HK-ayyiTwAAAAA:ySXJUH_4zsOWtktEyYKLusdGsLueDqHeY4Y1Sx3OioJjKKeIPWX01lbx5V4eQWGF-p4U2fPEA9Q">walking</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4929070/">running</a> and <a href="http://irep.ntu.ac.uk/id/eprint/33530/1/11030_Cooper.pdf">team games</a> (such as football and basketball). But this effect tends to only last for around one hour, so regular opportunities to be active across the school day are important.</p>
<p>Another really interesting discovery is that young people with higher levels of fitness demonstrate <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-020-09484-w">superior concentration</a>, when compared with less fit children. For example, young people who have higher cardiorespiratory fitness display better concentration than those who are less fit. So based on current evidence, regular physical activity appears to be very important for improving concentration in children.</p>
<figure class="align-center ">
<img alt="Two boys challenge each other for the ball during a football match." src="https://images.theconversation.com/files/374792/original/file-20201214-21-1sltqid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374792/original/file-20201214-21-1sltqid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374792/original/file-20201214-21-1sltqid.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374792/original/file-20201214-21-1sltqid.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374792/original/file-20201214-21-1sltqid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374792/original/file-20201214-21-1sltqid.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374792/original/file-20201214-21-1sltqid.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Team sports are especially good for concentration.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/boys-kicking-football-on-sports-field-172398914">Fotokostic/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Although there’s less evidence in adults, research does still show that acute bouts of physical activity, such as a 20 minute walk or jog, <a href="https://www.sciencedirect.com/science/article/pii/S0006899312004003?casa_token=4VvVk8VEeEQAAAAA:RNAGs9jDIA2bu13i47PjgMIbP1Axyeov0GNcUGGPu_U_zqPkvOSGhiCvg0Gl9ogOreE26QUfZpQ">enhance concentration</a> for up to one hour afterwards. Studies have also shown that having people take breaks for physical activity during the work day improves self-reported concentration and mood – both of which could improve productivity. Physical activity and higher levels of physical fitness have even been shown to benefit many parts of brain function – including concentration – in <a href="https://psycnet.apa.org/record/2015-55483-005">people aged 65 and over</a>.</p>
<p>We have less information though about the mechanisms that explain why physical activity improves our concentration. We think that it could be caused by certain psychological mechanisms – such as feeling more alert and having better mood following physical activity – that improve concentration. Increased blood flow to the brain and changes in the <a href="https://physoc.onlinelibrary.wiley.com/doi/full/10.14814/phy2.12163">parts of the brain</a> that are activated during and <a href="https://psycnet.apa.org/record/2011-02060-009">after exercise</a> have also been suggested.</p>
<h2>Get moving</h2>
<p>But which types of exercise are best? The simple answer to this question is that it depends on a lot of things.</p>
<p>Some evidence shows that any exercise which <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212482">requires decision making</a> (such as team games, like football and hockey) might be particularly beneficial to concentration, due to the fact that your brain is engaged during these types of exercise.</p>
<p>But research also shows that any exercise which is extremely vigorous or exhausting, such as high-intensity interval training workouts may – at least in the short-term – actually have a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5504581/#:%7E:text=Maximal%20intensity%20exercise%20in%20children,improve%20following%20a%20recovery%20period.">negative effect on concentration</a>, due to the fact that it’s very difficult to concentrate when exhausted.</p>
<p>The research is clear, however, that short bouts of moderate, physical activity are great at improving concentration immediately following exercise. This might include going for a brisk walk, a run, or even a leisurely cycle. But the best type of physical activity is one that you enjoy, and can be easily incorporated into daily life. Ultimately, people need to be able to regularly perform physical activity in order to gain both immediate and long-term benefits. </p>
<p>So if you spend a lot of time sitting at your desk during the work day, regular activity breaks will help you to keep your concentration on the task in hand. Even just taking your dog for a short walk or running to the shop for a quick errand will help.</p><img src="https://counter.theconversation.com/content/151143/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Cooper has received no research funding that directly impacts upon the content of this article.</span></em></p>Research shows short bouts of physical activity can boost your concentration for up to one hour.Simon Cooper, Senior Lecturer in Sport Science, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1502032020-11-17T13:55:35Z2020-11-17T13:55:35ZExercise and the brain: three ways physical activity changes its very structure<figure><img src="https://images.theconversation.com/files/369819/original/file-20201117-19-rox6nv.jpg?ixlib=rb-1.1.0&rect=6%2C6%2C4243%2C2816&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Our brain may depend on physical activity to stay healthy.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/senior-couple-making-nordic-walking-park-158289224">Slawomir Kruz/ Shutterstock</a></span></figcaption></figure><p>Regular exercise changes the structure of our bodies’ tissues in obvious ways, such as reducing the size of fat stores and increasing muscle mass. Less visible, but perhaps even more important, is the profound influence exercise has on the <a href="https://pubmed.ncbi.nlm.nih.gov/22470361/">structure of our brains</a> – an influence that can protect and preserve <a href="https://pubmed.ncbi.nlm.nih.gov/25977091/">brain health and function</a> throughout life. In fact, some experts believe that the human brain may <a href="https://www.nature.com/articles/487295a">depend on regular physical activity</a> to function optimally throughout our lifetime. </p>
<p>Here are just a few ways exercise changes the structure of our brain.</p>
<h2>Memory</h2>
<p>Many studies suggest that exercise can help protect our memory as we age. This is because exercise has been shown to prevent the loss of total brain volume (which can lead to lower cognitive function), as well as preventing shrinkage in specific brain regions associated with memory. For example, one magnetic resonance imaging (MRI) scan study revealed that in older adults, six months of exercise training <a href="https://academic.oup.com/biomedgerontology/article/61/11/1166/630432">increases brain volume</a>. </p>
<p>Another study showed that shrinkage of the hippocampus (a brain region essential for learning and memory) in older people can be <a href="https://pubmed.ncbi.nlm.nih.gov/21282661/">reversed by regular walking</a>. This change was accompanied by improved memory function and an increase of the protein <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2504526/">brain-derived neutropic factor</a> (BDNF) in the bloodstream. </p>
<p>BDNF is essential for healthy cognitive function due to its roles in cell survival, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6400842/">plasticity</a> (the brain’s ability to change and adapt from experience) and <a href="https://pubmed.ncbi.nlm.nih.gov/31440144/">function</a>. Positive links between exercise, BDNF and memory have been widely investigated and have been demonstrated in <a href="https://pubmed.ncbi.nlm.nih.gov/21722657/">young adults</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6135088/">older people</a>. </p>
<p>BDNF is also one of several proteins linked with adult neurogenesis, the brain’s ability to modify its structure by <a href="https://pubmed.ncbi.nlm.nih.gov/29467613/">developing new neurons</a> throughout adulthood. Neurogenesis occurs only in very few brain regions – one of which is the hippocampus – and thus may be a central mechanism involved in learning and memory. Regular physical activity may protect memory in the long term by <a href="https://pubmed.ncbi.nlm.nih.gov/30777641/">inducing neurogenesis</a> via BDNF. </p>
<p>While this link between exercise, BDNF, neurogenesis, and memory is very well described in animal models, experimental and ethical constraints mean that its importance to human brain function is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4565723/">not quite so clear</a>. Nevertheless exercise-induced neurogenesis is being actively researched as a potential therapy for <a href="https://pubmed.ncbi.nlm.nih.gov/29679070/">neurological and psychiatric disorders</a>, such as Alzheimer’s disease, Parkinson’s disease and depression. </p>
<h2>Blood vessels</h2>
<p>The brain is highly dependent on blood flow, receiving approximately 15% of the body’s entire supply – despite being only 2-3% of our body’s total mass. This is because our nervous tissues need a constant supply of oxygen to function and survive. When neurons become more active, blood flow in the region where these neurons are located <a href="https://pubmed.ncbi.nlm.nih.gov/27499087/">increases to meet demand</a>. As such, maintaining a healthy brain depends on maintaining a healthy network of blood vessels. </p>
<figure class="align-center ">
<img alt="An illustration of a person's brain and the blood vessels connected to it." src="https://images.theconversation.com/files/369820/original/file-20201117-15-1y13dn1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/369820/original/file-20201117-15-1y13dn1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369820/original/file-20201117-15-1y13dn1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369820/original/file-20201117-15-1y13dn1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369820/original/file-20201117-15-1y13dn1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369820/original/file-20201117-15-1y13dn1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369820/original/file-20201117-15-1y13dn1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Regular exercise helps blood vessels grow in the brain.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/human-brain-nervous-system-anatomy-3d-549239809">Magic mine/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Regular exercise increases the growth of new blood vessels in the brain regions where neurogenesis occurs, providing the increased blood supply that supports the development of these <a href="https://pubmed.ncbi.nlm.nih.gov/19212941">new neurons</a>. Exercise also improves the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357295/">health and function</a> of existing blood vessels, ensuring that brain tissue consistently receives adequate blood supply to meet its needs and preserve its function. </p>
<p>Finally, regular exercise can prevent, and even treat, <a href="https://pubmed.ncbi.nlm.nih.gov/33037326/">hypertension</a> (high blood pressure), which is a risk factor for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7392084">development of dementia</a>. Exercise works in <a href="https://pubmed.ncbi.nlm.nih.gov/30564547/">multiple ways</a> to enhance the health and function of blood vessels in the brain.</p>
<h2>Inflammation</h2>
<p>Recently, a growing body of research has centred on microglia, which are the resident immune cells of the brain. Their main function is to constantly <a href="https://pubmed.ncbi.nlm.nih.gov/25693054/">check the brain</a> for potential threats from microbes or dying or damaged cells, and to clear any damage they find.</p>
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Read more:
<a href="https://theconversation.com/microglia-the-brains-immune-cells-protect-against-diseases-but-they-can-also-cause-them-139232">Microglia: the brain’s 'immune cells' protect against diseases – but they can also cause them</a>
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</em>
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<p>With age, normal immune function declines and chronic, low-level inflammation occurs in body organs, including the brain, where it increases risk of <a href="https://pubmed.ncbi.nlm.nih.gov/32219178/">neurodegenerative disease</a>, such as Alzheimer’s disease. As we age, microglia become less efficient at clearing damage, and less able to prevent disease and inflammation. This means <a href="https://pubmed.ncbi.nlm.nih.gov/31704314/">neuroinflammation can progress</a>, impairing brain functions – including memory.</p>
<p>But recently, we’ve shown that exercise can <a href="https://pubmed.ncbi.nlm.nih.gov/31978523/">reprogramme these microglia</a> in the aged brain. Exercise was shown to make the microglia more energy efficient and capable of counteracting neuroinflammatory changes that impair brain function. Exercise can also modulate neuroinflammation in degenerative conditions like <a href="https://pubmed.ncbi.nlm.nih.gov/30564548/">Alzheimer’s disease</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/27313534/">multiple sclerosis</a>. This shows us the effects of physical activity on immune function may be an important target for therapy and disease prevention.</p>
<p>So how can we ensure that we’re doing the right kind of exercise – or getting enough of it – to protect the brain? As yet, we don’t have robust enough evidence to develop specific guidelines for brain health though findings to date suggest that the greatest benefits are to be gained by <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6527141/">aerobic exercise</a> – such as walking, running, or cycling. It’s recommended adults get a minimum of <a href="https://www.who.int/publications/i/item/9789241599979">150 minutes per week</a> of moderate intensity aerobic exercise, combined with activities that maintain strength and flexibility, to maintain good general health. </p>
<p>It must also be noted that researchers don’t always find <a href="https://pubmed.ncbi.nlm.nih.gov/30777641/">exercise has beneficial effect</a> on the brain in their studies – likely because different studies use different exercise training programmes and measures of cognitive function, making it difficult to directly compare studies and results. But regardless, plenty of research shows us that exercise is beneficial for many aspects of our health, so it’s important to make sure you’re getting enough. We need to be conscious of making time in our day to be active – our brains will thank us for it in years to come.</p><img src="https://counter.theconversation.com/content/150203/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Áine Kelly receives funding from Science Foundation Ireland. </span></em></p>Exercise plays an important part in preserving memory throughout our lifetime.Áine Kelly, Professor in Physiology, Trinity College DublinLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1400472020-07-22T19:48:16Z2020-07-22T19:48:16ZCoronavirus and the brain: Diagnosing and treating COVID-19’s neurological effects<figure><img src="https://images.theconversation.com/files/340995/original/file-20200610-34696-hz5lhr.jpg?ixlib=rb-1.1.0&rect=245%2C49%2C4914%2C3571&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A patient is prepared for neurocognitive assessment.</span> <span class="attribution"><span class="source">(Steven Kim)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>As the number of COVID-19 patient records grows, researchers are meticulously combing through the data, searching for a better understanding of the virus and what we can expect in the months and years ahead. What is now of increasing concern in health care is the realization that the virus can not only be severe, but can also have long-term consequences. </p>
<p><a href="https://dx.doi.org/10.1016%2Fj.ijantimicag.2020.106024">Respiratory and skeletal muscle consequences</a> surfaced earlier in the pandemic. More recently, the <a href="https://www.washingtonpost.com/health/2020/06/07/coronavirus-ventilators-prolonged-comas/">neurological</a> and <a href="https://grants.nih.gov/grants/guide/notice-files/NOT-NS-20-051.html">neurocognitive aspects</a> of the virus have become a major concern. The <a href="https://doi.org/10.1186/s13054-019-2626-z">neurocognitive symptoms linked to coronaviruses</a>, counting COVID-19, include delirium, both acute and chronic attention and <a href="https://doi.org/10.1111/apha.13473">memory deficits linked to hippocampal and cortical damage</a>, as well as learning deficits in both adults and <a href="https://journals.sagepub.com/doi/10.1177/0883073808331362">children</a>.</p>
<p>These symptoms feature significantly in a large percentage of COVID-19 patients. In March, <a href="https://doi.org/10.1016/j.bbi.2020.03.031">a study reported 36.4 per cent of COVID-19 patients have neurological symptoms</a>, including headache, disturbed consciousness and paresthesia (a burning or prickling sensation in parts of the body such as hands, legs and feet). Not surprisingly, severely affected patients are more likely to develop neurological symptoms than patients who have mild or moderate disease. </p>
<p>More recently, <a href="https://doi.org/10.1056/NEJMc2008597">a report published in early June in the <em>New England Journal of Medicine</em></a> reported that 84 per cent of the patient sample had neurologic symptoms. Also, <a href="https://doi.org/10.1016/S2213-2600(20)30076-X">a recent paper in the <em>Lancet</em></a> using autopsy reports on patients who had severe cases noted brain tissue edema (a life-threatening condition that causes fluid to develop in the brain, causing pressure inside the skull) and neuronal degeneration (when a brain’s neurons break down, lose connectivity and affect brain function). </p>
<h2>Assessing neurological symptoms</h2>
<p>The percentage of COVID-19 patients with neurological symptoms varies greatly between studies. One of the reasons is inconsistent assessment methods. Research has shown behavioural assessment (testing based on things like the patient’s visual responses, motor function and communication) is <a href="https://doi.org/10.1002/ana.24962">frequently inaccurate</a>. </p>
<figure class="align-center ">
<img alt="Closeup of a man's face in profile, with an electrode in place on his forehead and another beside his eye." src="https://images.theconversation.com/files/348192/original/file-20200717-19-13b4vkr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/348192/original/file-20200717-19-13b4vkr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/348192/original/file-20200717-19-13b4vkr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/348192/original/file-20200717-19-13b4vkr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/348192/original/file-20200717-19-13b4vkr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/348192/original/file-20200717-19-13b4vkr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/348192/original/file-20200717-19-13b4vkr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Objectively measuring brain function enables accurate diagnosis and appropriate treatment.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Reliable neurocognitive assessment procedures will be essential both in accurately assessing active and post-COVID patients’ cognitive abilities, and in tracking their recovery. Objective assessments of brain function can help pinpoint when neurocognitive symptoms begin to appear in COVID-19 patients, which patient groups are at a higher risk, how long neurological effects may last and what treatments are most effective. In the early stages of understanding COVID-19 and researching the neurological effects, definitive facts around these issues remain unknown. </p>
<p>Our McMaster University laboratory has pioneered the direct measurement of real-time brain function using electroencephalogram-based (EEG-based) neuroimaging to assess neurocognitive function.</p>
<p><a href="https://doi.org/10.1016/S0003-9993(99)90035-7">We have used EEG-based methods for many years</a> to study the <a href="https://doi.org/10.1016/S1388-2457(02)00224-9">cognitive problems</a> that often accompany brain injuries, including disorders of consciousness such as “vegetative state” (now often called unresponsive wakefulness syndrome), coma and <a href="https://doi.org/10.1038/s41598-019-53751-9">concussion</a>.</p>
<p>Using unique prompts, data collection and machine-learning algorithms, we can now observe brain activity at significantly higher resolution by analyzing results based on data obtained in increments of two to three minutes instead of 20 to 30 minutes. This means we can see rapidly occurring changes in brain function with unprecedented speed. The ability to objectively measure a patient’s brain function has a vital impact on their trajectory, and helps avoid misdiagnosis and provide appropriate treatment. </p>
<p>We’ve even been able to correct some misconceptions about neurocognitive function after a brain injury. <a href="https://ieeexplore.ieee.org/document/7590863">In some coma patients</a>, we found rapidly fluctuating brain activity that reflects variations in consciousness — proof of brain activity that had a high risk of being missed by earlier testing methods. We have also identified clear <a href="https://doi.org/10.1016/j.clinph.2018.10.013">markers of neurocognitive dysfunction</a> in so-called “invisible injuries,” such as <a href="https://doi.org/10.1093/braincomms/fcaa063">mild traumatic brain injuries (concussions</a>), even <a href="https://doi.org/10.1109/TNSRE.2019.2922553">when the patient’s most recent concussion occurred decades earlier</a>. </p>
<p>Our laboratory partnered with a McMaster neurotech startup called <a href="https://voxneuro.com/">VoxNeuro</a> to make the method available to health-care providers and their patients outside of research settings after requests from our health-care research partners to use the method clinically. Together, we are well-positioned to use these same pioneering assessment methods in COVID-19 patients. </p>
<p>The neurocognitive techniques my colleagues and I have developed use advanced acquisition and analysis methods to examine electrophysiological activity in the brain. The result is electrophysiological recordings and observed responses (called event-related potentials, or ERPs) that have a number of important and in some cases unique features that lend themselves to studying typical cognitive functions like memory, attention and decision making — commonly referred to as mental abilities. They are particularly suitable for testing vulnerable patients. </p>
<figure class="align-center ">
<img alt="Line graph with time as x-axis and amplitude as y-axis, showing a red line for brain waves of a control patient and a blue line for a concussed patient. Red line has greater amplitude variation than blue, with N1 and MMN points much higher." src="https://images.theconversation.com/files/345864/original/file-20200706-3958-1h8ag3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345864/original/file-20200706-3958-1h8ag3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345864/original/file-20200706-3958-1h8ag3u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345864/original/file-20200706-3958-1h8ag3u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345864/original/file-20200706-3958-1h8ag3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=523&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345864/original/file-20200706-3958-1h8ag3u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=523&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345864/original/file-20200706-3958-1h8ag3u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=523&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Brain wave forms recorded by our EEG methodologies comparing brain responses of healthy controls to a patient who has suffered a concussion. The N1 (indicative of auditory and visual processing) and MMN (indicative of automatic attention) ERP responses in the patient’s data are significantly reduced compared to controls.</span>
<span class="attribution"><span class="source">(John Connolly)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>First, recording a person’s electrophysiological responses is non-invasive: no elements of the technology require injections or inhalation of any substances. The technology is compatible with other medical devices such as pacemakers. </p>
<p>Particularly useful for vulnerable patients is its point-of-care feature: we can test a patient at the bedside, in the intensive care unit or in their home. We are able to objectively measure the size of brain responses and the all-important timing of these responses with millisecond accuracy. This reveals specific neurocognitive dysfunctions with great accuracy, which means doctors can tailor treatment and rehabilitation to each patient’s needs. </p>
<p><a href="https://doi.org/10.1212/WNL.0000000000009455">COVID-19’s “neuro-invasive” features</a> are leading to calls to prepare for the consequences of the daunting <a href="https://doi.org/10.1212/WNL.0000000000009673">relationship between COVID-19 and neurologic pathologies</a>. As more patients recover, we need to continue to monitor them as they return to their everyday lives. Are they functioning as they did before they caught the virus? Or are they experiencing difficulties returning to work, with complications concentrating or maintaining focus? </p>
<p>It’s not enough to monitor a patient until they recover from the obvious life-threatening complications of the illness. Patients require continued monitoring to detect potential long-term effects and treat them proactively. If cognitive consequences go untreated, they can manifest into much worse complications that are harder to fix the longer they are left alone. </p>
<p>There are lessons to be learned from the history of related coronaviruses, where <a href="https://link.springer.com/chapter/10.1007%2F978-81-322-1777-0_6">research has noted neuro-invasive features</a> leading to learning and memory problems in adults and <a href="https://doi.org/10.1080/00365540802669543">children</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Ak13wfnB3ys?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The ability to objectively assess brain function in COVID-19 patients offer information about when neurocognitive effects begin, how long they last and who is at risk.</span></figcaption>
</figure>
<p>Another vital question for health-care response efforts is: <a href="https://doi.org/10.1515/jtim-2016-0016">How are medical interventions for COVID-19 affecting brain function</a>? Do certain pharmaceutical drugs or ventilators have a negative impact? As much as we need to better understand the virus with objective data, we need to understand, objectively, <a href="https://www.nbcnews.com/health/health-news/post-intensive-care-syndrome-why-some-covid-19-patients-may-n1166611">what interventions help or harm patients at scale</a>. These are the questions that we are looking to answer in upcoming research through engagements with critical care specialists and <a href="https://cancovid.ca">CanCOVID</a> — Canada’s expert-led COVID-19 response.</p>
<p>It’s only been half a year since this virus started to come into view, and <a href="https://www.cnn.com/2020/06/09/health/fauci-coronavirus-worst-nightmare/index.html">scientists and clinicians are still striving to understand how it works</a> and what damage it leaves behind. As we begin to plan for COVID-19’s massive social, medical and economic legacies, our lab is proud to open a window into how it changes our body’s most complex and important system.</p><img src="https://counter.theconversation.com/content/140047/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr. John F. Connolly is the Senator William McMaster Chair of Cognitive Neuroscience of Language at McMaster University, and co-founder and Chief Science Officer of VoxNeuro.
His research has received support from national and international funding agencies including:
Natural Science and Engineering Research Council of Canada (NSERC),
Canadian Institutes of Health Research (CIHR),
Canada Foundation for Innovation,
Ontario Brain Institute (OBI),
Ontario Centres of Excellence (OCE),
Scottish Rite Charitable Foundation (Canada & USA),
March of Dimes Research Foundation (USA),
National Institutes of Health (USA),
Heart and Stroke Foundation of Canada,
The Hospital for Sick Children (Sick Kids),
Networks of Centres of Excellence of Canada,
Autism Speaks’ High Risk - High Impact Initiatives (USA),
Collaborative Health Research Projects (CIHR & NSERC).
VoxNeuro has received innovation support funding from the National Research Council of Canada Industrial Research Assistance Program (NRC IRAP).</span></em></p>COVID-19 is not just a respiratory disease. Its neurocognitive symptoms are not well defined yet, so assessment is key to understanding the effects of coronavirus on the brain.John F. Connolly, Professor and Senator Wm. McMaster Chair; Director, ARiEAL Research Centre; co-director of Language, Memory & Brain Laboratories, McMaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1248422019-11-17T13:13:05Z2019-11-17T13:13:05ZFake news grabs our attention, produces false memories and appeals to our emotions<figure><img src="https://images.theconversation.com/files/301629/original/file-20191113-77363-17oq2zn.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4167%2C4154&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fake news works at a cognitive level to shape our perceptions and drive our decisions.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>“Fake news” is a relatively new term, yet it’s now seen as one of the greatest threats to democracy and free debate. In the Netflix documentary <em>The Great Hack</em> — which chronicled the rise and fall of Cambridge Analytica — we saw how Facebook data was used to target potential voters with insidious right-wing propaganda packaged as if it were news. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/iX8GxLP1FHo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Trailer for the Netflix documentary ‘The Great Hack.’</span></figcaption>
</figure>
<p>But how does fake news work? Neuroscience can provide at least some insight.</p>
<h2>Grabbing attention</h2>
<p>The first job of fake news is to catch our attention, and for this reason, novelty is key. Psychologists Gordon Pennycook and David Rand suggested that <a href="https://doi.org/10.1016/j.cognition.2018.06.011">one of the reasons hyperpartisan claims are so successful is that they tend to be outlandish</a>.</p>
<p>In a world full of surprises, humans have developed an exquisite ability to rapidly detect and orient towards unexpected information or events. Novelty is an essential concept underlying the neural basis of behavior, and plays a role at nearly all stages of neural processing. </p>
<p>Sensory neuroscience has shown that only <a href="https://doi.org/10.1016/j.neunet.2004.12.004">unexpected information can filter through to higher stages of processing</a>. The sensory cortex may have therefore evolved to adapt to, to predict, and to quiet down the expected regularities of our experiences, focusing on events that are unpredictable or surprising. Neural responses gradually reduce each time we are exposed to the same information, as the brain learns that this stimulus has no reward associated with it. </p>
<p>Novelty itself is related to motivation. Dopamine, a neurotransmitter associated with reward anticipation, <a href="https://doi.org/10.1037/a0037128">increases when we are confronted by novelty</a>. When we see something new, we recognize its potential for rewarding us in some way. Further studies show that <a href="https://doi.org/10.1523/JNEUROSCI.2680-08.2008">the ability of the hippocampus to create new synaptic connections between neurons (a process known as plasticity) is increased by the influence of novelty</a>. By increasing the plasticity of the brain, the potential for learning new concepts is increased. </p>
<h2>Fake news, false memory</h2>
<p>The primary region involved in responding to novel stimuli — the substantia nigra/ventral segmental area or SN/VTA — is closely linked to the hippocampus and the amygdala, both of which play important roles in learning and memory. While the hippocampus compares stimuli against existing memories, the amygdala responds to emotional stimuli and strengthens associated long-term memories. </p>
<p>This aspect of learning and memory formation is of particular interest to my own lab, where we study brain oscillations involved in long-term memory consolidation. This process occurs during sleep, a somewhat limited time frame to integrate all of our daily information. For this reason, the brain is adapted to prioritise certain types of information. Highly emotionally provocative information stands a stronger chance of lingering in our minds and being incorporated into long-term memory banks. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/301656/original/file-20191113-77310-u66fml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/301656/original/file-20191113-77310-u66fml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/301656/original/file-20191113-77310-u66fml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/301656/original/file-20191113-77310-u66fml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/301656/original/file-20191113-77310-u66fml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/301656/original/file-20191113-77310-u66fml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/301656/original/file-20191113-77310-u66fml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/301656/original/file-20191113-77310-u66fml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Our brains conoslidate long-term memories during sleep.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The allure of fake news is therefore reinforced by its relationship to memory formation. A recent study, published in <em>Psychological Science</em>, highlighted that <a href="https://doi.org/10.1177%2F0956797619864887">exposure to propaganda may induce false memories</a>. In one of the largest false-memory experiments to date, scientists gathered up registered voters in the Republic of Ireland in the week preceding the 2018 abortion referendum. </p>
<p>Half of the participants reported a false memory for at least one fabricated event, with more than one third of participants reporting a specific, “eye-witness” memory. In-depth analysis revealed that voters were most susceptible to forming false memories for fake news that closely aligned with their beliefs, particularly if they had low cognitive ability.</p>
<h2>Emotional appeals</h2>
<p>The ability of fake news to grab our attention and then highjack our learning and memory circuitry goes a long way to explaining its success. But its strongest selling point is its ability to appeal to our emotions. Studies of online networks show <a href="https://doi.org/10.1073/pnas.1618923114">text spreads more virally</a> when it contains a high degree of “moral emotion,” which drives everything we do. </p>
<p>Decisions are often driven by deep-seated emotion that can be difficult to identify. In the process of making a judgment, people consult or refer to an emotion catalogue carrying all the positive and negative tags consciously or unconsciously associated with a given context. </p>
<p>We rely on our ability to place information into an emotional frame of reference that combines facts with feelings. Our positive or negative feelings about people, things and ideas arise much more rapidly than our conscious thoughts, long before we’re aware of them. This processing operates with exposures to emotional content as short as 1/250th of a second, “<a href="https://doi.org/10.1016/j.ejor.2005.04.006">an interval so brief that there is no recognition or recall of the stimulus.</a>” </p>
<p>Merely being <a href="https://psycnet.apa.org/record/2018-46919-001">exposed to a fake news headline can increase later belief</a> in that headline, so scrolling through social media feeds laden with emotionally provocative content has the power to change the way we see the world and make political decisions.</p>
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Read more:
<a href="https://theconversation.com/how-fake-news-gets-into-our-minds-and-what-you-can-do-to-resist-it-114921">How fake news gets into our minds, and what you can do to resist it</a>
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<p>The novelty and emotional conviction of fake news, and the way these properties interact with the framework of our memories, exceeds our brains’ analytical capabilities. Though it’s impossible to imagine a democratic structure without disagreement, no constitutional settlement can function if everything is a value judgement based on misinformation. </p>
<p>In the absence of any authoritative perspective on reality, we are doomed to navigate our identities and political beliefs at the mercy of our brains’ more basal functions. The capacity to nurture and sustain peaceful disagreement is a positive characteristic of a truly democratic political system. </p>
<p>But before democratic politics can begin, we must be able to distinguish between opinions and facts, fake news and objective truth.</p>
<p>[ <em>Deep knowledge, daily.</em> <a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/124842/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>R m N does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We fall sway to fake news because it grabs our attention through outlandish claims, suggests false memories and contains appeals to our emotions that align with our politics.R m N, PhD Student, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1263142019-11-13T11:21:13Z2019-11-13T11:21:13ZHow simple policy changes can help us age better and prevent cognitive decline<figure><img src="https://images.theconversation.com/files/301373/original/file-20191112-178511-r00zvz.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C4193%2C2785&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ensuring older people can continue to socialise is important for preventing loneliness and cognitive decline. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/group-senior-friends-chatting-416231764?src=750ff30e-cf7f-44e0-9e41-3d5b64188ddb-1-2">Pressmaster/ Shutterstock</a></span></figcaption></figure><p>Many people experience a decline in cognitive function with age, such as a worsening memory and trouble processing information. In most cases, this is perfectly normal. In some cases, however, age-related cognitive decline may affect a person’s ability to carry out complex tasks, such as managing finances or preparing a meal. At times, it may even make it difficult for a person to perform daily tasks, such as dressing and feeding. </p>
<p>Around 18% of the UK’s population is <a href="https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/articles/overviewoftheukpopulation/july2017">aged 65 and older</a>. By 2030, it’s estimated that <a href="https://www.ageuk.org.uk/globalassets/age-uk/documents/reports-and-publications/later_life_uk_factsheet.pdf">one in five UK people</a> will be aged over 65. </p>
<p>But this doesn’t account for the number of people who will experience cognitive decline and dementia as they age. Incidence of dementia sharply rises at the age of 75 – and it is expected that the number of people in the UK living with dementia <a href="https://www.ncbi.nlm.nih.gov/books/NBK513075/">could triple by 2050</a>. Cognitive function is very important to older people’s well-being. It influences <a href="https://www.ncbi.nlm.nih.gov/books/NBK513075/">everything they do</a>, including working and socialising, and has a huge social and economic impact on families. Finding ways to prevent cognitive decline is increasingly important.</p>
<p>We’re often told that the solution to cognitive decline lies in <a href="https://www.alz.co.uk/news/biogen-and-eisai-announce-plans-to-file-for-market-approval-of-alzheimers-drug">new medicines or therapies</a> that can reduce symptoms, or by following a <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)32350-9/fulltext">healthy lifestyle</a>. </p>
<p>But recent research by our team found that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3950961/">social and emotional well-being</a> – meaning our feelings of being connected to family and the community, and our subjective experience of positive or negative emotions – may be just as important as therapy and lifestyle for maintaining good cognitive function in older age. <a href="https://g2aging.org/">Numerous studies</a> from around the world have found that social connectedness and loneliness influence older people’s cognitive function, including their memory. </p>
<p>Loneliness affects <a href="https://www.tandfonline.com/doi/abs/10.1080/00223980.2011.609572">approximately 9% of people</a> over 65 in the UK. It’s a complex emotional state where people perceive their social interactions and individual relationships to be inadequate. </p>
<p><a href="https://www.elsa-project.ac.uk/">One major study on ageing</a> – which collects data from more than 18,000 UK over-50s about physical and mental health, well-being, finances and attitudes towards ageing – found that isolation and loneliness were associated with poorer memory, especially among those with lower levels of education. In addition, loneliness in older age was associated with a <a href="https://academic.oup.com/ije/advance-article/doi/10.1093/ije/dyz085/5485775">steeper decline in cognitive function</a>. This included worse memory and verbal fluency. </p>
<h2>Cognitive decline and loneliness</h2>
<p>Although these findings are staggering, they also show us how difficult it is to establish if loneliness causes cognitive decline, or if cognitive decline causes loneliness. One way to find out is by looking at whether interventions to reduce loneliness also inadvertently affect older people’s cognitive health too. </p>
<p>We addressed this question in a series of studies looking at the impact that free bus travel had on over-60s. When the UK government gave free bus travel to people over 60 in 2006, it was thought that the measure may reduce loneliness and increase social engagement as it enables older people to remain connected to their social environments. </p>
<p><a href="https://academic.oup.com/aje/article/188/10/1774/5525029">We found</a> that free bus travel significantly increased public transportation use but, in addition, it led to improvements in cognitive function – particularly, improved memory. </p>
<p><a href="https://jech.bmj.com/content/72/5/361">In another study</a>, we found that increased public transportation use also reduced depression and feelings of loneliness. It increased participation in volunteering activities and contact with older people’s adult children and friends. These findings show how a simple policy has had unintended positive consequences. It led to significant improvements in older people’s cognitive function and mental health – potentially by influencing social well-being. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/301515/original/file-20191113-77363-1fddgvg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/301515/original/file-20191113-77363-1fddgvg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/301515/original/file-20191113-77363-1fddgvg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/301515/original/file-20191113-77363-1fddgvg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/301515/original/file-20191113-77363-1fddgvg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/301515/original/file-20191113-77363-1fddgvg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/301515/original/file-20191113-77363-1fddgvg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Public transport increased community participation, which improved cognitive function and well-being.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/nottingham-nottinghamshire-uk-05282017-three-old-1092811700?src=39224da0-c962-4edc-840b-0128cd0be1dd-1-18&studio=1">Simon Annable/ Shutterstock</a></span>
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<p>This isn’t the first time we’ve found how social policy changes can help protecting older people against cognitive decline. For example, <a href="https://jech.bmj.com/content/73/4/370">we examined the impact</a> of a French law that increased the minimum legal school leaving age by 2 years in 1959, from 14 to 16 years of age.</p>
<p>This law effectively increased the years of schooling for French adults presently reaching old age. We found that even decades after leaving school, a longer period in education helped older adults maintain cognitive function – particularly memory – and postponed cognitive decline. </p>
<p>Even policies that affect the whole economy have been found to be an important factor in health and memory. We found that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6018975/">older people exposed to an economic recession</a> in the years leading up to their retirement experience faster cognitive decline in their post-retirement years. This suggests that policies that protect older people from the impact of economic decline might help them to maintain good cognitive function in older age. </p>
<p>Long-term care policies that enable older people to maintain independence and continue to socialise may also be important. “<a href="https://www.nia.nih.gov/health/aging-place-growing-older-home">Ageing in place</a>”, an approach that emphasises the importance of supporting older people to continue living in their home and community, has led many governments to offer care for older people with limitations in their own home. </p>
<p><a href="https://www.palgrave.com/gp/book/9783319689685">Our research suggests</a> that only a small fraction of older Europeans that have difficulty performing daily activities (such as dressing, walking or washing) are actually eligible to receive home care through the government. </p>
<p>But we also found that an increase in the amount of care that people receive at home through government-sponsored programmes, paradoxically, <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/hec.3665">increases the amount of assistance they receive</a> from friends and family. This suggests that a long-term policy that expands access to home care may help older people maintain social ties, mental well-being, and cognitive function well into older age.</p>
<p>While prospects such as new drugs that protect against cognitive ageing are exciting, research shows that many simple policy changes can also promote social and emotional well-being – which may be just as important for maintaining brain function in later life. Even in the face of declining physical ability, programmes that provide long-term care at home may be critical for maintaining cognitive function and leading a <a href="https://www.pnas.org/content/116/4/1207">meaningful life at older age</a>.</p><img src="https://counter.theconversation.com/content/126314/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mauricio Avendano (<a href="mailto:mauricio.avendano_pabon@kcl.ac.uk">mauricio.avendano_pabon@kcl.ac.uk</a>) receives funding from the Economic and Social Research Council (ESRC), the National Institute for Health Research (NIHR) and the European Commission Horizon2020 Programme. </span></em></p><p class="fine-print"><em><span>Ludovico Carrino is research fellow at the Department of Global Health & Social Medicine at King's College London. He receives funding from the Economic and Social Research Council and the European Commission Horizon 2020 Programme. He is affiliated with the Department of Economics at the Ca' Foscari University of Venezia.</span></em></p>Simple policies, such as the free bus pass for older adults, not only reduce loneliness but also help older people maintain cognitive function.Mauricio Avendano Pabon, Professor of Public Policy & Global Health, King's College LondonLudovico Carrino, Research fellow, King's College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1231082019-10-02T13:00:05Z2019-10-02T13:00:05ZThe forgotten benefits of a ‘bad’ memory<figure><img src="https://images.theconversation.com/files/294557/original/file-20190927-185394-ppiej0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/business-man-forgetful-793633621?src=o6jf08jGrjKyDiSRQ498Zg-1-93">Shutterstock/FOTOKITA</a></span></figcaption></figure><p>Memory is the essence of our psychological functioning, essential for every move we make – getting dressed, having breakfast, driving to work, doing a crossword, making a cup of tea. Nothing we do in our conscious daily lives does not require memory. </p>
<p>So, given our reliance on it, why is it that memory sometimes – or often – lets us down? And is this something to be concerned about, or might it actually be healthy?</p>
<p>Consider some of the many ways in which our memories feel like they’re not working properly. There’s the name you’re told on meeting someone new which you forget within seconds; the act of going upstairs to get something and then forgetting what you went there for; or blissfully remembering a foreign holiday several years ago without any memory of the incident at the airport that upset the family.</p>
<p>It’s probably true that everyone can relate to each of these memory “failures” – and indeed they are failures. But it may be that we should not be overly concerned about them.</p>
<p>The various types of forgetting involve different issues. For example, sometimes it’s clear that we simply haven’t set a proper memory down in our mind in the first place, like when we forget why we went upstairs. </p>
<p>In other cases there is clearly a memory there, but it’s just not retrievable – such as when a name you know is on the tip of your tongue. Or perhaps the memory has been altered in some regard along the way, when you’re convinced something happened on a Thursday, yet all the facts point to it being a Tuesday.</p>
<p>So what is memory for, and why is forgetfulness such a prevalent experience? Memory serves to give us a record of our lives, to situate us in the present and to plan for the future. It is essential to a sense of self. And while memory lapses can be frustrating, there are ways around them, which can sometimes be beneficial to that sense of self. </p>
<p>If I am constantly forgetting where I put my keys, I develop a routine to deal with the situation. It’s a simple but effective solution which requires practice (and remembering to enact): always put your keys in the same place. </p>
<p>Or, if I want to remember someone’s name, I ensure that on meeting them, I make an extra effort to register their face, say their name aloud, and perhaps try to associate it with someone else of the same name. (Apparently one of former US president Bill Clinton’s strengths as a charismatic politician was that he <a href="https://www.oprah.com/omagazine/oprah-interviews-president-bill-clinton/2">always remembered people’s names</a> – but this certainly wouldn’t have come without a level of deliberate concentration.)</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/295202/original/file-20191002-49346-pwbpy6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/295202/original/file-20191002-49346-pwbpy6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/295202/original/file-20191002-49346-pwbpy6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/295202/original/file-20191002-49346-pwbpy6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/295202/original/file-20191002-49346-pwbpy6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/295202/original/file-20191002-49346-pwbpy6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/295202/original/file-20191002-49346-pwbpy6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Right where you left them.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/new-keys-inserted-into-mortise-lock-1473658121?src=tQqaSNOg6apTtdq-ObadZA-2-32">Shutterstock/ROMSVETNIK</a></span>
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<p>And if I remember a totally happy holiday and repress the negative incident at the airport, this actually helps me feel better about myself and my experience. I have subconsciously edited out the negative aspect to create a more positive recollection. </p>
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Read more:
<a href="https://theconversation.com/how-sleep-makes-the-brain-forget-things-new-research-on-mice-123636">How sleep makes the brain forget things – new research on mice</a>
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<p>Another interesting example of this kind of beneficial “self-editing” is where long-term couples will say to their other half: “I love you more today than yesterday.” When psychologists examined this concept, they found it not to be entirely true. Instead, <a href="https://psycnet.apa.org/record/1999-00166-004">they found</a> that long-term couples have a commitment to each other that is important for their own personal well being. So if I feel I love you more than yesterday, it is ultimately beneficial to feeling positive about myself – even if it is not objectively true.</p>
<h2>Remember to forget</h2>
<p>Most people’s memories fail them regularly, and this is because our minds have a limited ability to process all the information in our environment. It simply is not feasible to remember everything we experience.</p>
<p>That said, there are rare cases of people who claim to have “super memories”. They can remember what the weather was like on March 6 2016, for example, or what they had for lunch on the September 15 2004. One of those “super mnemonists” <a href="https://thepsychologist.bps.org.uk/volume-26/edition-10/interview-would-you-want-super-memory">has described</a> the ability as “a curse [which] plays over and over in my mind”. </p>
<p>The reality of remembering everything would be an overwhelming experience. So for most of us, forgetting things is not just normal – but desirable. </p>
<p>Regular memory failures can often be deliberately and methodically overcome, while changes in memory over time are often due to people maintaining a positive sense of self. And that’s worth remembering.</p><img src="https://counter.theconversation.com/content/123108/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Catriona Morrison does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Your memory may be unreliable – but that can be an advantage.Catriona Morrison, Professor of Psychology, University of BradfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1220322019-10-01T12:28:24Z2019-10-01T12:28:24ZLow blood pressure could be a culprit in dementia, studies suggest<figure><img src="https://images.theconversation.com/files/294224/original/file-20190925-51463-11h3qy4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Low blood pressure may cause problems for many older people.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/healthcare-hospital-medicine-concept-doctor-patient-420121216?src=H1sVmDH-2Hn6K77DB-ICsA-1-10">Satyrenko/Shutterstock.com</a></span></figcaption></figure><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596698/">Decline in brain function</a> often occurs as people age. People often worry that declining brain function is an inevitable part of growing old and will lead to dementia, but it is not. Many people do not experience age-related cognitive decline.</p>
<p>Clinical studies that have followed older individuals over many years have consistently demonstrated that chronically low blood pressure increases the risk of age-related cognitive decline. For example, a <a href="https://alzres.biomedcentral.com/articles/10.1186/s13195-017-0262-x">study</a> published in 2017 followed more than 24,000 people for up to 27 years. This study showed that low blood pressure is a significant predictor of cognitive decline and the probability of developing dementia. This was independent of age, gender, weight, cardiovascular, kidney or diabetic status.</p>
<p>Low blood pressure is associated with decreased blood flow to the brain when an individual is sitting or standing. Many researchers have come to believe that <a href="https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.117.027448">insufficient brain blood flow</a> plays a critical role in the development of dementia, Alzheimer’s and perhaps even Parkinson’s disease. Some believe that it may even play the primary role.</p>
<p>Those of us who study the link between low blood pressure and cognitive performance need to determine what “too low” a blood pressure means in an individual person. This would allow health care providers to know when to intervene and correct a person’s low blood pressure. <a href="https://scholar.google.com/citations?user=VcXxSfkAAAAJ&hl=en">My team and I</a> at the Clinical Science and Engineering Research Lab at Binghamton University are addressing this question.</p>
<h2>What constitutes low blood pressure?</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/294220/original/file-20190925-51414-magy8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/294220/original/file-20190925-51414-magy8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=380&fit=crop&dpr=1 600w, https://images.theconversation.com/files/294220/original/file-20190925-51414-magy8y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=380&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/294220/original/file-20190925-51414-magy8y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=380&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/294220/original/file-20190925-51414-magy8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=478&fit=crop&dpr=1 754w, https://images.theconversation.com/files/294220/original/file-20190925-51414-magy8y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=478&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/294220/original/file-20190925-51414-magy8y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=478&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Old age does not mean that a person loses brain function, but the low blood pressure that some elders experience may lead to such loss of function.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-old-man-155118443?src=Sq3sGeYY0wdZH5a85dBUlg-1-11">OneSmallSquare/Shutterstock.com</a></span>
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<p>In our research, we are utilizing data obtained from <a href="https://www.accessdata.fda.gov/cdrh_docs/reviews/DEN130033.pdf">a relatively new quantitative assessment tool</a> cleared by the FDA for evaluating cognitive function in people over the age of 50 years, who have a high school degree or higher educational level.</p>
<p>This computer-based evaluation, which takes about 10 minutes for an individual to complete, provides clinicians and researchers with a reproducible assessment of cognitive function on a scale of 0-100. A score above 75 places the person in the expected cognitive function range for their age, while a score between 50 and 75 indicates an individual is in the below-normal range – and correspondingly, at increased risk of developing dementia. A score below 50 is indicative of an individual having many characteristics of dementia syndrome. </p>
<p>We have been comparing cognitive function scores in 50-95-year-olds to their resting blood pressures. <a href="https://www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings">Blood pressure</a> is determined by measuring how much pressure is required to stop blood flow in the arteries of your arm. Resting blood pressure refers to your blood pressure after you have been sitting quietly for 10-15 minutes in a nonstressful environment. This is the blood pressure most older Americans experience most of the day, as older Americans are, on average, sedentary for over <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5081718/">9 hours</a>. </p>
<p>Our <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5617084/">previous work</a> showed that of the two components of blood pressure – <a href="https://www.healthline.com/health/high-blood-pressure-hypertension/blood-pressure-reading-explained">systolic and diastolic</a> – diastolic blood pressure is the better predictor of cognitive performance. Diastolic blood pressures measures your blood pressure when your heart is relaxing and is the “lower number” of your blood pressure reading. We are focusing on this aspect of blood pressure.</p>
<p>Though our study is ongoing, two clear patterns are already developing in the data we have obtained from healthy subjects who have volunteered to be in the study - that is, people who have not been diagnosed with dementia or any other cognitive disorder. </p>
<p><iframe id="4Mc9A" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/4Mc9A/4/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>First, low resting diastolic blood pressure is remarkably common. Over 85% of otherwise healthy 50-95-year-old subjects, in our study, have below normal resting diastolic blood pressures. This observation, by itself, would not necessarily be cause for concern. However, three-fourths of those we have studied so far, a total of 42 to date, with below normal blood pressure also test in the “below normal” cognitive function range. </p>
<p>Low blood pressure, also called <a href="https://www.mayoclinic.org/diseases-conditions/low-blood-pressure/symptoms-causes/syc-20355465">hypotension</a>, is usually defined as having a blood pressure low enough to cause dizziness, blurry vision or fainting. These symptoms typically occur with a diastolic pressure below 60 millimeters of mercury, or mmHg. Doctors tend not to be concerned about low blood pressure until diastolic pressure falls below this level. </p>
<p>Our data indicate that even individuals with diastolic blood pressures well above this 60mmHg threshold are unable to support normal cognitive function when upright. Indeed, at essentially any resting diastolic blood pressure below normal (80mmHg), the trend in the data indicates that cognitive performance in older adults is significantly reduced. Interestingly, these results are consistent with earlier reports of detrimental influences of low blood pressure on cognitive function even in <a href="https://www.ncbi.nlm.nih.gov/pubmed/14673692">young adults</a>. </p>
<h2>The surprising role of calf muscles</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/294230/original/file-20190925-51405-mx42tc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/294230/original/file-20190925-51405-mx42tc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/294230/original/file-20190925-51405-mx42tc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/294230/original/file-20190925-51405-mx42tc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/294230/original/file-20190925-51405-mx42tc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/294230/original/file-20190925-51405-mx42tc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/294230/original/file-20190925-51405-mx42tc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The soleus muscles on the back of the calf.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/muscles-posterior-leg-soleus-gastrocnemius-muscle-1254777964?src=ercfJumZatqWT5_ksOJ6Ww-1-20">Joaquin Corbalan P/Shutterstock.com</a></span>
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<p>Low diastolic pressure can arise as a result of medication use, heart failure or other health complications. But, in most people, it is simply a matter of the heart not pumping out enough blood with each stroke; in other words, <a href="https://www.ncbi.nlm.nih.gov/pubmed/27957701">low cardiac output</a>. And low cardiac output occurs when not enough blood is being returned to the heart from the lower body. </p>
<p>The soleus muscles, specialized muscles in the middle of your lower legs, are responsible for pumping blood back up to the heart. Over the last decade, our research team has demonstrated how the soleus muscles plays a critical role in maintaining normal blood pressure during sedentary activities.</p>
<p>An effective strategy for maintaining normal blood pressure, and brain blood flow, is to <a href="https://www.ncbi.nlm.nih.gov/pubmed/18760165">“re-train”</a> your soleus muscles. These deep postural muscles are most active during activities such as sustained squatting or toe standing. You can rebuild these muscles by regularly undertaking such activities, though it requires hours a day of exercise.</p>
<p>Alternatively, “passive exercise” options exist which permit the “training-up” of your soleus muscles more conveniently. Both <a href="https://www.ncbi.nlm.nih.gov/pubmed/30200088">electrical</a> and <a href="https://www.physiology.org/doi/full/10.1152/ajpregu.00513.2004?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed&">mechanical</a>, soleus stimulation approaches have been shown to significantly increase venous return to the heart. </p>
<p>Preliminary clinical studies have also provided <a href="https://www.dovepress.com/reversal-of-cognitive-impairment-in-a-hypotensive-elderly-population-u-peer-reviewed-article-CIA">confirming evidence</a> that raising resting diastolic blood pressure through daily soleus muscle stimulation, over a period of several months, can reverse the cognitive impairment associated with aging.</p>
<p>No treatments currently exist for dementia, and no potential treatment seems to be on the horizon, and so the health care community has become much more focused on slowing, or reversing, cognitive aging to prevent progression to dementia. </p>
<p>If interventions to eliminate chronically low diastolic blood pressure are simple and direct, we may well have the opportunity to largely eliminate much of the scourge of dementia from modern life.</p>
<p>[ <em>You respect facts and expertise. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=yourespect">You can read us daily by subscribing to our newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/122032/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kenneth McLeod owns shares in Sonostics, Inc. which provided partial support to complete this research. </span></em></p>Researchers are looking for ways to determine who’s most at risk for dementia and also ways to detect it early. A scientist who has studied low blood pressure makes a case for a link between the two.Kenneth McLeod, Professor of Systems Science, and Director - Clinical Science and Engineering Research Laboratory, Binghamton University, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1195852019-07-02T11:14:07Z2019-07-02T11:14:07ZWill they ever wake up? New study on consciousness after brain injury shows ‘maybe’<figure><img src="https://images.theconversation.com/files/281820/original/file-20190628-94688-tuw6q8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A new study on consciousness could help answer the question"will they ever wake up?"</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/magnetic-resonance-image-mri-scan-brain-560923147?src=HyyclycWLE_EDjrx5tWc-Q-2-31&studio=1"> create jobs 51/shutterstock.com</a></span></figcaption></figure><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5234377/">Acute brain injury</a> can result in significant damage and loss of consciousness, warranting life support and admission to an intensive care unit. A complex journey toward recovery begins, sometimes involving daily life-and-death battles. </p>
<p>As the acuity of the life-threatening injury declines and the patient’s condition stabilizes a bit, the dust starts to settle. But then so many questions begin. </p>
<p>“Will they ever wake up?” is one of the most common and challenging questions that families navigating this emotional rollercoaster journey ask us. </p>
<p>It is also one of the most daunting questions for care teams. As in many situations, the honest and so unfulfilling answer has to be, “We don’t know.”</p>
<p>We are both neurologists specializing in neurocritical care, with clinical and research interests in acute brain damage and outcomes. We think a <a href="http://dx.doi.org/10.1056/NEJMoa1812757">recent study</a> provides new insights into the wide spectrum of states between consciousness and unconsciousness, and opens intriguing possibilities for further research, and perhaps predicting outcomes. </p>
<h2>How do care teams try to determine if someone is conscious?</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/281822/original/file-20190628-94712-1iky3ve.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/281822/original/file-20190628-94712-1iky3ve.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281822/original/file-20190628-94712-1iky3ve.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281822/original/file-20190628-94712-1iky3ve.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281822/original/file-20190628-94712-1iky3ve.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281822/original/file-20190628-94712-1iky3ve.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281822/original/file-20190628-94712-1iky3ve.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Neurological machines are used to help read brain activity.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/laboratory-man-wearing-brainwave-scanning-headset-1036798345?src=kRAd7KRiWvq4dEuDp-2BNw-1-21&studio=1">Gorodenkoff/shutterstock.com</a></span>
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<p>Let’s start by defining <a href="https://www.merriam-webster.com/dictionary/consciousness">consciousness</a>, or the ability to maintain alertness and to be aware and interact with the surroundings. Physicians prompt patients to follow instructions such as “Wiggle your toes” and “Stick out your tongue,” in order to assess their level of awareness and delineate signs of consciousness. </p>
<p>What is traditionally termed a “simple command” actually requires a complex array of brain functions in order to be carried out correctly. Hearing needs to be intact, the meaning of the commands to be understood and processed, planning of the expected task to be on point, and last, the nerves telling the respective muscles to contract need to be functioning. <a href="http://dx.doi.org/10.1056/NEJMoa0905370">Different areas of the brain are activated</a> depending on the task being planned or performed.</p>
<p>A tool that can help is an <a href="https://www.healthline.com/health/eeg">electroencephalogram</a>, or EEG, which tests brain waves. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3379170/">Functional brain imaging</a>, such as functional MRI, is another tool used to gain more insight into what is going on inside a brain by monitoring the change in activity of certain areas, especially, if no such “simple commands” can be executed. </p>
<p>However, none of these means so far has offered a granular insight into what exactly is going on “in there,” or even if there is someone trapped “in there,” so early in the course of severe acute brain injury.</p>
<h2>New insights may bring new promise</h2>
<p>In the <a href="http://dx.doi.org/10.1056/NEJMoa1812757">recent study</a> published in the New England Journal of Medicine, neurointensive care physicians – doctors who take care of patients with brain injury in intensive care – and researchers took brain wave analysis to the next level. They connected unresponsive patients with acute brain injury to continuous EEG, and asked them to perform simple commands while their brain waves were being recorded. The EEG data then were fed into a machine-learning algorithm derived from healthy volunteers, which compared the change in brain activity from the state while at rest to the activity recorded following the commands.</p>
<p>Of 104 patients studied, 15% showed activation of brain activity corresponding to the command, even though bedside examiners did not see any visible response – a phenomenon termed cognitive-motor dissociation.</p>
<p>In a particularly striking finding, the researchers found that patients who showed brain activation were more than three times as likely, compared to those who showed no brain activation, to make strides in recovery and gain at least partial independence over the year following the brain injury. They were also nearly twice as likely to be able to demonstrate visible response and actually follow commands by the end of their hospital stay.</p>
<p>This finding is important because, for the first time, scientists could see such a pattern of hidden brain activity in unresponsive patients early after severe brain injury and connect these findings to long-term outcomes, suggesting that such activity might be an early sign for recovery. </p>
<h2>Where does this lead?</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/281823/original/file-20190628-94720-75ogdt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/281823/original/file-20190628-94720-75ogdt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281823/original/file-20190628-94720-75ogdt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281823/original/file-20190628-94720-75ogdt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281823/original/file-20190628-94720-75ogdt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281823/original/file-20190628-94720-75ogdt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281823/original/file-20190628-94720-75ogdt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Even after the study, there are still questions about consciousness we need to answer.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/laboratory-man-wearing-brainwave-scanning-headset-1036798345?src=kRAd7KRiWvq4dEuDp-2BNw-1-21&studio=1">Gorodenkoff/shutterstock.com</a></span>
</figcaption>
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<p>Does this answer all our questions about consciousness?</p>
<p>Certainly not. Many questions remain. Several assessments of brain activity in the same patient showed that detection of <a href="https://news.weill.cornell.edu/news/2015/10/editorial-new-terminology-needed-for-brain-injured-patients">cognitive-motor dissociation </a> was not a static phenomenon, but rather inconsistent. This makes sense, as even healthy brains go through phases such as deep sleep where one would likely not activate their brain when called to “wiggle your toes.”</p>
<p>However, in the setting of an intensive care unit normal sleep-wake cycles are disturbed. Also, patients often are sedated, and the presence of sedative drugs might interfere with these assessments. Further, even without clear outer stimuli, fluctuations in the level of neurologic function are common in patients with brain injury throughout their ICU stay. Thus, the findings of this study still need to be replicated in different patients and places.</p>
<p>Consciousness is much more than what we humans are able to detect with our bare eyes, even for seasoned experts. Combined with a technology that is five years short of celebrating its 100th birthday since the first EEG recording in 1924, artificial intelligence has demonstrated its potential to enhance the yield of EEG in illuminating the black box of the brain. </p>
<p>This study allows a peek under an iceberg and may transform how we practice neurologic outcome prediction. The use of machine learning to process data that the human eye would not be able to appreciate has already started to revolutionize the field of medicine. But, we also have to accept that this is just the beginning. What that means is that in many instances, when relatives ask “Will they ever wake up?” in the first few days after a severe brain injury, the honest answer still is “We don’t know.” But the patient might hear us already. </p>
<p>[ <em><a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=thanksforreading">Thanks for reading! We can send you The Conversation’s stories every day in an informative email. Sign up today.</a></em> ]</p><img src="https://counter.theconversation.com/content/119585/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katharina Busl serves on the Board of Directors of "The Art of Medicine", a non-for-profit organization that supports brain injury research </span></em></p><p class="fine-print"><em><span>Carolina B. Maciel receives funding from Claude D. Pepper Older Americans Independence Center Junior Scholar award that supports pre-clinical studies of mechanisms of secondary brain injury in a rodent cardiac arrest model. </span></em></p>Consciousness has long been debated, particularly in the decades since devices have been used to keep people alive after brain injury. A new study suggests that some people can “wake up” after injury.Katharina M. Busl, Associate Professor of Neurology; Chief of the Division of Neurocritical Care, Department of Neurology, University of FloridaCarolina B. Maciel, Assistant Professor of Neurology; Director of Research for the Division of Neurocritical Care, Department of Neurology, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1169822019-05-24T10:44:42Z2019-05-24T10:44:42ZPeople with traumatic brain injury, who often lose empathy, can regain it with treatment<figure><img src="https://images.theconversation.com/files/275953/original/file-20190522-187165-7bot3u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Understanding the facial cues from another person is a component of empathy.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sad-man-listening-advice-colleague-during-690911812?src=YLMUcA7ngh2FRkp9dGmLiw-1-76">Pressmaster/Shutterstock.com</a></span></figcaption></figure><p>Most people can easily determine when a loved one is feeling sad or anxious. This recognition will often trigger the person to offer a comforting gesture or even have a <a href="https://en.wikipedia.org/wiki/Emotional_contagion">contagious emotional</a> reaction, causing them to also feel sad or anxious, too. </p>
<p>These important actions are referred to as emotion recognition and empathy, and they are fundamental to establishing human emotional connections and relationships.</p>
<p>But imagine waking up one morning and your loved one lost the ability to recognize and empathize with your feelings. For the last couple of decades, researchers have been showing this to be a common outcome for people who have suffered a traumatic brain injury. The inability to <a href="https://psycnet.apa.org/record/2011-06479-001">recognize</a> and <a href="https://www.cambridge.org/core/journals/journal-of-the-international-neuropsychological-society/article/inability-to-empathize-following-traumatic-brain-injury/A3AA1F6B946F6A71F156BF76D3E7FE2A">empathize</a> with others’ emotions after brain injury has a resounding impact on family and friends and has sparked research leading to promising treatments.</p>
<p>I started studying emotion recognition and empathy in 2005, and this is exactly how the wife of my first research participant described it happened for her husband who was in a car accident and suffered a traumatic brain injury, or TBI. Once a very affectionate partner who responded to all of her emotional needs, he now failed to recognize her sadness or comfort her when she lost her father. Conversely, he was unable to feel the emotional contagion of her joy when she received recognition at work. This once very strong couple later divorced.</p>
<h2>Crashes, blasts and falls that affect millions</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/275952/original/file-20190522-187153-1wmlwep.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275952/original/file-20190522-187153-1wmlwep.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275952/original/file-20190522-187153-1wmlwep.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275952/original/file-20190522-187153-1wmlwep.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275952/original/file-20190522-187153-1wmlwep.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275952/original/file-20190522-187153-1wmlwep.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275952/original/file-20190522-187153-1wmlwep.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Falls are a common cause of traumatic brain injury, but car and motorcycle crashes also are major causes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/construction-worker-falling-off-ladder-inside-521522911?src=INAi_gpaECFoioEX2l7XOA-1-35">Andre Marcelo Santa Maria/Shutterstock.com</a></span>
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<p>A <a href="https://www.biausa.org/brain-injury/about-brain-injury/basics/overview">TBI</a> is when an external physical force leads to a disruption in brain function. Falls and motor vehicle accidents are the most common causes, but damage also results from many other injuries, including blast injuries that are frequently experienced by active duty military. </p>
<p>In 2014, almost <a href="https://www.cdc.gov/traumaticbraininjury/get_the_facts.html">3 million Americans</a> received some type of medical care or died from a TBI-related incident. Problems with attention, memory, planning, reasoning or problem solving are common. But often more troublesome are the frequent emotional and behavioral changes, such as increased anger and aggression. Emotional and behavioral changes have been linked with problems recognizing others’ emotions and an inability to share another’s feelings. </p>
<p>Prevalence rates of <a href="https://psycnet.apa.org/record/2011-06479-001">problems with emotion recognition</a> and <a href="https://www.cambridge.org/core/journals/journal-of-the-international-neuropsychological-society/article/inability-to-empathize-following-traumatic-brain-injury/A3AA1F6B946F6A71F156BF76D3E7FE2A">decreased empathy</a> after brain injury are 39% and 60%, respectively. </p>
<p>This is quite concerning for people with TBI and their family members, as this impairment has been related to worse <a href="https://www.tandfonline.com/doi/abs/10.1080/02699052.2018.1531301">social relations</a> after TBI. </p>
<h2>The first step of empathy</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/275955/original/file-20190522-187189-tut1fk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275955/original/file-20190522-187189-tut1fk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275955/original/file-20190522-187189-tut1fk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275955/original/file-20190522-187189-tut1fk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275955/original/file-20190522-187189-tut1fk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275955/original/file-20190522-187189-tut1fk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275955/original/file-20190522-187189-tut1fk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A boy responds to a girl’s look of pain.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-boy-hugging-consoling-upset-girl-1164198340?src=YLMUcA7ngh2FRkp9dGmLiw-1-46">fizkes/Shutterstock.com</a></span>
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<p>It has been a longstanding <a href="https://journals.sagepub.com/doi/abs/10.1177/1534582304267187">theory</a> that a person must recognize others’ emotions in order to empathize with them.</p>
<p>However, despite the strong theoretical rationale, scientific experiments have had trouble finding strong support for this belief, in people <a href="https://journals.lww.com/headtraumarehab/Abstract/2014/01000/Relationships_Between_Alexithymia,_Affect.13.aspx">with</a> and <a href="https://www.safetylit.org/citations/index.php?fuseaction=citations.viewdetails&citationIds%5B%5D=citjournalarticle_261580_38">without</a> brain injury. </p>
<p>When I looked at how the past studies were conducted, I saw clear design flaws. Many of the former studies assessed emotion recognition and empathy in isolation of one another. Empathy was typically measured with unrelated subjective questionnaires. So it is not too surprising little relationship was found between two unrelated tests. </p>
<p>For example, researchers would administer an emotion recognition test, such as pictures of facial expressions. The researchers would then give participants a questionnaire about their general empathic tendencies. But the researchers did not test how the person with TBI felt in response to the facial expressions they had to identify. For example, did they feel sad when looking at a sad person? By not gauging a person’s feelings in response to the emotional expression in the picture, researchers were not measuring a direct empathic response to another’s feelings. </p>
<h2>A second step to empathy</h2>
<p>Due to the limitations of previous studies, my colleague, <a href="https://spectre.cqu.edu.au/profiles/view/10920"></a><a href="https://scholar.google.com/scholar?hl=en&as_sdt=0%2C15&q=barbra+zupan&btnG=&oq=barbra+z">Dr. Barbra Zupan</a>, and I decided to take a different approach. In our <a href="https://doi.org/10.1016/j.apmr.2018.07.431">recent publication</a>, we showed subjects with and without TBI emotional film clips and had them identify how the character in the clip felt and how they felt while watching the clip. </p>
<p>Since a shared emotional response is an element of empathy, when participants felt the same emotion they identified the character to be feeling, we defined that as an empathic response. We did not require them to recognize the character’s emotion accurately to be classified as an empathic response. Using this approach allowed us to measure the direct relationship between recognizing another’s emotion and having a shared empathic response. If we made accurate emotion recognition a requirement to be considered an empathic response, we would not have been able to measure this relationship. </p>
<p>We had several interesting findings. Based on past research showing <a href="https://www.cambridge.org/core/journals/journal-of-the-international-neuropsychological-society/article/inability-to-empathize-following-traumatic-brain-injury/A3AA1F6B946F6A71F156BF76D3E7FE2A">impaired empathy</a> after TBI, we expected the percent of empathic responses to be pretty low in our participants with TBI. While participants with TBI did not have as many empathic responses as their uninjured age and gender matched peers (79%), they did respond empathically 67% of the time. </p>
<p>Further, we found that accurate recognition of characters’ emotions was associated with a greater number of empathic responses. The empathic responses of participants with TBI more than doubled when they accurately identified the character’s emotion, compared to a misrecognized emotion (71% vs. 32%, respectively). </p>
<p>We think it is important to note that correct emotion recognition was not sufficient for an empathic response to occur in either group. That is, participants did not always respond empathically when they correctly recognized the emotion.</p>
<p>Our findings also suggest that participants with TBI had a harder time recognizing and empathizing with sad and fearful emotions, compared to happy emotions. This was indicated by their lower recognition and empathic responses when characters were acting sad and afraid. This means that when loved ones need comforting the most – when feeling fearful or sad – they are unlikely to get it from a partner with TBI.</p>
<h2>Helping those with TBI</h2>
<p>We think these findings have important clinical implications.</p>
<p>First, clinicians treating people with TBI should plan to evaluate emotion recognition and empathy in their patients and learn how to treat these impairments. Interviewing patients with TBI and their family members can help paint a picture of how a person has changed compared to his or her pre-injury self and lead to goals for rehabilitation. There are <a href="https://journals.lww.com/headtraumarehab/Abstract/2015/05000/A_Randomized_Controlled_Trial_of_Emotion.12.aspx">evidence-based approaches and free treatment tools</a>, designed by our group, that have now been deemed <a href="https://www.archives-pmr.org/article/S0003-9993(19)30194-7/abstract">practice standards</a> for improving emotion recognition skills. </p>
<p>When training emotion recognition after TBI, clinicians should also discuss with the patient ways they can respond empathically to loved ones. <a href="https://www.ingentaconnect.com/content/wk/htr/2017/00000032/00000005/art00010">Newer research</a> from another group in the Netherlands shows that this combination – both recognition and responding empathically – is effective and should involve the family member as part of treatment. </p>
<p>Also, clinicians should consider educating survivors of TBI and their families about these common changes after TBI, why it happens, what they might expect in terms of changes in behavior, and notifying them that it could improve with treatment. </p>
<p>Finally, family members could be directed to be more explicit about their emotions and what they would like from their loved one with a brain injury. Together, these efforts could improve outcomes after TBI and minimize the common relationship strains experienced after a brain injury.</p><img src="https://counter.theconversation.com/content/116982/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dawn Neumann has received funding from the Cannon Research Center at Carolinas Rehabilitation, The Humanity Research Institute at Brock University, and the National Institute on Disability, Independent Living and Rehabilitation Research (grant no. H133G080043)</span></em></p>Millions of people suffer traumatic brain injuries, and many lose the ability to emotionally connect with others. A new study suggests there’s a way to help them regain their ability to connect.Dawn Neumann, Associate Professor of Physical Medicine & Rehabilitation, IUPUILicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1080742019-02-06T19:16:53Z2019-02-06T19:16:53ZCan bees do maths? Yes – new research shows they can add and subtract<figure><img src="https://images.theconversation.com/files/249896/original/file-20181211-76962-cfh85r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Can we have a count of all the honeycomb cells please? </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/bees-on-honeycomb-480038002?src=l2Pxo6VObiG61ZMwTnIxZw-1-102">from www.shutterstock.com </a></span></figcaption></figure><p>The humble honeybee can use symbols to perform basic maths including addition and subtraction, shows new research published today in the journal <a href="http://advances.sciencemag.org/content/5/2/eaav0961">Science Advances</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/kCucnmIULGU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Bee have miniature brains - but they can learn basic arithmetic.</span></figcaption>
</figure>
<p>Despite having a brain containing less than one million neurons, the honeybee has recently shown it can manage complex problems – like <a href="https://theconversation.com/bees-join-an-elite-group-of-species-that-understands-the-concept-of-zero-as-a-number-97316">understanding the concept of zero</a>. </p>
<p>Honeybees are a high value model for exploring questions about neuroscience. In our latest study we decided to test if they could learn to perform simple arithmetical operations such as addition and subtraction. </p>
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Read more:
<a href="https://theconversation.com/which-square-is-bigger-honeybees-see-visual-illusions-like-humans-do-87673">Which square is bigger? Honeybees see visual illusions like humans do</a>
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<h2>Addition and subtraction operations</h2>
<p>As children, we learn that a plus symbol (+) means we have to add two or more quantities, while a minus symbol (-) means we have to subtract quantities from each other. </p>
<p>To solve these problems, we need both long-term and short-term memory. We use working (short-term) memory to manage the numerical values while performing the operation, and we store the rules for adding or subtracting in long-term memory.</p>
<p>Although the ability to perform arithmetic like adding and subtracting is not simple, it is vital in human societies. The Egyptians and Babylonians <a href="https://www.ancient.eu/article/1012/ancient-egyptian-taxes--the-cattle-count/">show evidence of using arithmetic</a> around 2000BCE, which would have been useful – for example – to count live stock and calculate new numbers when cattle were sold off. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/250130/original/file-20181211-76977-ln6tw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/250130/original/file-20181211-76977-ln6tw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/250130/original/file-20181211-76977-ln6tw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=188&fit=crop&dpr=1 600w, https://images.theconversation.com/files/250130/original/file-20181211-76977-ln6tw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=188&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/250130/original/file-20181211-76977-ln6tw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=188&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/250130/original/file-20181211-76977-ln6tw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=236&fit=crop&dpr=1 754w, https://images.theconversation.com/files/250130/original/file-20181211-76977-ln6tw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=236&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/250130/original/file-20181211-76977-ln6tw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=236&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This scene depicts a cattle count (copied by the Egyptologist Lepsius). In the middle register we see 835 horned cattle on the left, right behind them are some 220 animals and on the right 2,235 goats. In the bottom register we see 760 donkeys on the left and 974 goats on the right.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Counts_tomb_75_gizeh-lepsius.png">Wikimedia commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>But does the development of arithmetical thinking require a large primate brain, or do other animals face similar problems that enable them to process arithmetic operations? We explored this using the honeybee. </p>
<h2>How to train a bee</h2>
<p>Honeybees are central place foragers – which means that a forager bee will return to a place if the location provides a good source of food. </p>
<p>We provide bees with a high concentration of sugar water during experiments, so individual bees (all female) continue to return to the experiment to collect nutrition for the hive. </p>
<p>In our setup, when a bee chooses a correct number (see below) she receives a reward of sugar water. If she makes an incorrect choice, she will receive a bitter tasting quinine solution. </p>
<p>We use this method to teach individual bees to learn the task of addition or subtraction over four to seven hours. Each time the bee became full she returned to the hive, then came back to the experiment to continue learning.</p>
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Read more:
<a href="https://theconversation.com/are-they-watching-you-the-tiny-brains-of-bees-and-wasps-can-recognise-faces-100884">Are they watching you? The tiny brains of bees and wasps can recognise faces</a>
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<h2>Addition and subtraction in bees</h2>
<p>Honeybees were individually trained to visit a Y-maze shaped apparatus. </p>
<p>The bee would fly into the entrance of the Y-maze and view an array of elements consisting of between one to five shapes. The shapes (for example: square shapes, but many shape options were employed in actual experiments) would be one of two colours. Blue meant the bee had to perform an addition operation (+ 1). If the shapes were yellow, the bee would have to perform a subtraction operation (- 1). </p>
<p>For the task of either plus or minus one, one side would contain an incorrect answer and the other side would contain the correct answer. The side of stimuli was changed randomly throughout the experiment, so that the bee would not learn to only visit one side of the Y-maze. </p>
<p>After viewing the initial number, each bee would fly through a hole into a decision chamber where it could either choose to fly to the left or right side of the Y-maze depending on operation to which she had been trained for. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/249545/original/file-20181209-128187-1kd5s0f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249545/original/file-20181209-128187-1kd5s0f.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=671&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249545/original/file-20181209-128187-1kd5s0f.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=671&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249545/original/file-20181209-128187-1kd5s0f.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=671&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249545/original/file-20181209-128187-1kd5s0f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=844&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249545/original/file-20181209-128187-1kd5s0f.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=844&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249545/original/file-20181209-128187-1kd5s0f.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=844&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Y-maze apparatus used for training honeybees.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<p>At the beginning of the experiment, bees made random choices until they could work out how to solve the problem. Eventually, over 100 learning trials, bees learnt that blue meant +1 while yellow meant -1. Bees could then apply the rules to new numbers.</p>
<p>During testing with a novel number, bees were correct in addition and subtraction of one element 64-72% of the time. The bee’s performance on tests was significantly different than what we would expect if bees were choosing randomly, called chance level performance (50% correct/incorrect)</p>
<p>Thus, our “bee school” within the Y-maze allowed the bees to learn how to use arithmetic operators to add or subtract. </p>
<h2>Why is this a complex question for bees?</h2>
<p>Numerical operations such as addition and subtraction are complex questions because they require <a href="https://www.hindawi.com/journals/ijz/2011/806589/">two levels of processing</a>. The first level requires a bee to comprehend the value of numerical attributes. The second level requires the bee to mentally manipulate numerical attributes in working memory. </p>
<p>In addition to these two processes, bees also had to perform the arithmetic operations in working memory – the number “one” to be added or subtracted was not visually present. Rather, the idea of plus one or minus “one” was an abstract concept which bees had to resolve over the course of the training.</p>
<p>Showing that a bee can combine simple arithmetic and symbolic learning has identified numerous areas of research to expand into, such as whether other animals can add and subtract.</p>
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Read more:
<a href="https://theconversation.com/bees-get-stressed-at-work-too-and-it-might-be-causing-colony-collapse-96412">Bees get stressed at work too (and it might be causing colony collapse)</a>
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<h2>Implications for AI and neurobiology</h2>
<p>There is a lot of interest in AI, and how well computers can enable self learning of novel problems. </p>
<p>Our new findings show that learning symbolic arithmetic operators to enable addition and subtraction is possible with a miniature brain. This suggests there may be new ways to incorporate interactions of both long-term rules and working memory into designs to improve rapid AI learning of new problems. </p>
<p>Also, our findings show that the understanding of maths symbols as a language with operators is something that many brains can probably achieve, and helps explain how many human cultures independently developed numeracy skills.</p>
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<p><em>This article has been published simultaneously in Spanish on <a href="https://theconversation.com/pueden-aprender-matematicas-los-insectos-hemos-ensenado-a-una-colmena-de-abejas-a-sumar-y-restar-111297">The Conversation Espana</a>.</em></p><img src="https://counter.theconversation.com/content/108074/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Scarlett Howard received funding for this project from The Company of Biologists and the Australian Government. </span></em></p><p class="fine-print"><em><span>Adrian Dyer and Jair Garcia do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Bee brains contain less than one million neurons. Despite this, new research shows the honeybee can use symbols to perform basic maths, including addition and subtraction.Scarlett Howard, PhD candidate, RMIT UniversityAdrian Dyer, Associate Professor, RMIT UniversityJair Garcia, Research fellow, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/969832018-05-31T03:41:06Z2018-05-31T03:41:06ZLike sightseeing in Paris – a new model for brain communication<figure><img src="https://images.theconversation.com/files/220250/original/file-20180524-51115-sueg3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Oui! There is more than one way to navigate to the Eiffel Tower. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/docsearls/14212344956/in/photolist-nDTZ1h-7qWL5c-eYWwjB-UsjvTc-afbZ6W-bSVnpB-a82PaD-8a6mJW-ae7X66-6vAmnu-eTP7sA-8MwJf8-7Zz4M3-pvXUJS-bBFqrJ-75AHAP-75AGzp-6Y3LAK-57Yhqx-drKebS-79qPWG-dG664-VFWcRp-6boCHD-dxW17F-ae7VNF-8a5iEW-dNbXDK-dutWaM-8MwHNr-aWFd9e-VFMZWZ-8ZD8M2-7TUQoa-6PWoFQ-5U21b-q4atz-2NUkfN-p29mCW-pHaFK4-ZmCrDC-4dHbjU-6Y366z-mco9CK-qui2SD-LajkT-8Nfg6s-nhg5i-CA1i5h-e69nM6">docsearls/flickr </a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Many of our most common, debilitating and socially expensive health problems involve our brains – such as dementia, depression and drug addiction. </p>
<p>We know that regions of our brain are constantly sending and receiving electrical signals through a vast network of nerve connections, and that this exchange of information is crucial for all aspects of brain function.</p>
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Read more:
<a href="https://theconversation.com/how-injuries-change-our-brain-and-how-we-can-help-it-recover-91952">How injuries change our brain and how we can help it recover</a>
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<p>Yet <a href="https://www.nature.com/articles/nrn.2017.149">scientists don’t know how</a> signals find their way through the complex maze of connections in order to go from one region of the brain to another. </p>
<p>In our <a href="http://www.pnas.org/content/early/2018/05/29/1801351115">recently published paper</a>, we propose a communication model to explain how brain networks can be navigated to achieve efficient information transfer.</p>
<p>We’ll use an analogy to explain. </p>
<h2>Find the Eiffel Tower</h2>
<p>Imagine you are on vacation in Paris. You leave your hotel one morning hoping to walk to the Eiffel Tower. Two options to get there come to mind. </p>
<p>You could use your map of the city (or, more likely, your phone), and calculate the quickest, most direct route to get to your destination. </p>
<p>Alternatively, you might be adventurous and decide to try to find your own way to the Eiffel Tower without using a map. Assuming that you can see the famous tower in the distance, you could walk in the direction that seems to bring you closer to it, using this strategy to choose where to go each time you reach the intersection of two streets. </p>
<p>While this approach might be more exciting, it will probably take you longer to get to the tower. Also, it’s possible that you could get lost, and never get there at all.</p>
<p>The <a href="https://www.nature.com/articles/nrn2575">traditional models</a> of brain network communication are akin to a tourist who walks around Paris with a map. They presume that signals travel along the quickest and most direct route between two brain regions, following directions given by a central map of all nerve interconnections. </p>
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Read more:
<a href="https://theconversation.com/take-it-from-me-neuroscience-is-advancing-but-were-a-long-way-off-head-transplants-95930">Take it from me: neuroscience is advancing, but we're a long way off head transplants</a>
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<p>This would certainly have advantages for us – quick routes mean faster and more reliable communication. </p>
<p>However, this idea has recently been questioned, because there is <a href="http://www.pnas.org/content/111/2/833">no evidence</a> that such a map exists anywhere in the brain.</p>
<p>Our research shows that the brain can be navigated without a map, much like a tourist might find their way to the Eiffel Tower based only on landmarks and surroundings. </p>
<p>It turns out that brain networks are organised in a way that allows for a simple navigation strategy. To go from one starting region (that is, the hotel) to a destination region (the Eiffel Tower), signals can move along to the next connected region that brings them closest to the destination. Following this simple rule, signals can gradually get closer and closer to their destination by moving from region to region, until they arrive at the desired location in the brain.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/220573/original/file-20180528-80637-1j1jtqi.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/220573/original/file-20180528-80637-1j1jtqi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/220573/original/file-20180528-80637-1j1jtqi.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=331&fit=crop&dpr=1 600w, https://images.theconversation.com/files/220573/original/file-20180528-80637-1j1jtqi.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=331&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/220573/original/file-20180528-80637-1j1jtqi.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=331&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/220573/original/file-20180528-80637-1j1jtqi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=416&fit=crop&dpr=1 754w, https://images.theconversation.com/files/220573/original/file-20180528-80637-1j1jtqi.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=416&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/220573/original/file-20180528-80637-1j1jtqi.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=416&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Network model of the brain (right), alongside a pictorial representation of brain anatomy (left; from Wikimedia Commons). In the network model, the red path shows the quickest way to travel between the highlighted regions, only using three connections of the network. The green path shows the route identified by our navigation strategy, which use four connections. The red path is faster, but it was computed using a map of all connections. The green path was computed without a map, following our navigation strategy.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We found that this strategy can identify successful navigation routes between more than 90% of all possible pairs of brain regions. Also, these routes were, on average, 70-80% as quick as the fastest routes computed from a central map of all neuronal interconnections.</p>
<p>In other words, according to our new model, brain signals might work like people navigating around a large city like Paris - but without getting lost on the way, and almost as quickly as if they followed the instructions of a map or GPS.</p>
<h2>Modelling the brain as a network</h2>
<p>How did we come up with this model?</p>
<p>In the case of the human brain, we can find out how different regions are interconnected using an approach called diffusion magnetic resonance imaging (<a href="https://www.sciencedirect.com/science/article/pii/S089662730300758X">dMRI</a>).</p>
<p>Using this technique, we build network models of the brain known as “connectomes”, which tell us about the nerve fibres that connect different regions of the brain.</p>
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<h3>A tractogram showing all white matter nerve fibres in the brain. These nerve fibres connect all regions in the brain, allowing for signals to travel between them.</h3>
<iframe src="https://giphy.com/embed/2zdlSyT0EpiyAhuwNQ" width="100%" height="424" frameborder="0" class="giphy-embed" allowfullscreen=""></iframe>
<p><a href="https://giphy.com/gifs/brain-neuroscience-2zdlSyT0EpiyAhuwNQ">via GIPHY</a></p>
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<p>Representing the brain as a network helps scientists understand <a href="https://www.elsevier.com/books/fundamentals-of-brain-network-analysis/fornito/978-0-12-407908-3">big picture</a> organisational and functional properties of the brain.</p>
<p>We studied how efficiently the brains of humans, macaques (a kind of monkey) and mice can be navigated. For all species, we found that the way their brain networks are organised allows for efficient navigation between regions, without the need for a central map of connections. </p>
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Read more:
<a href="https://theconversation.com/neuroscience-in-pictures-the-best-images-of-the-year-89077">Neuroscience in pictures: the best images of the year</a>
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<p>Unfortunately, <a href="https://www.nature.com/articles/nrn.2017.149">today’s brain imaging technology</a> doesn’t allow us to see individual communication events happening in the brain. What we propose is a model of brain network communication that matches what we currently know about the structure and function of mammalian brains.</p>
<p>An important shortcoming of our Paris analogy is that while you may be able to walk to the Eiffel Tower without a map, we assumed that you could see it from afar. Similarly, our communication model assumes that brain regions “know” how far from each other they are in the brain. </p>
<p>While what is “known” by elements in the brain remains to be determined, our work shows that a central map is not necessary for efficient neural communication.</p>
<h2>We need to know more</h2>
<p>The exchange of electrical signals across brain regions underpins consciousness, perception and higher cognition. Changes to the way neural communication happens may be related to mental health issues and other brain disorders. </p>
<p>Communication models such as the one we have proposed, together with the development of <a href="https://www.sciencedirect.com/science/article/pii/S1053811917300666">technologies to track</a> the propagation of electrical signals, will take us closer to deciphering how the brain works in health and disease.</p><img src="https://counter.theconversation.com/content/96983/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Caio Seguin receives funding from the University of Melbourne. </span></em></p><p class="fine-print"><em><span>Andrew Zalesky receives funding from the National Health and Medical Research Council (NHMRC) of Australia and the Australian Research Council (ARC). </span></em></p>Brain signals might work like people navigating without a map – and it’s actually more efficient than you think.Caio Seguin, PhD candidate, The University of MelbourneAndrew Zalesky, Associate Professor of Biomedical Engineering and Psychiatry, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/933202018-03-20T14:30:14Z2018-03-20T14:30:14ZThe science behind the red mist (and how fish can help with anger management)<figure><img src="https://images.theconversation.com/files/210620/original/file-20180315-104635-19qtkw8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">shutterstock</span> </figcaption></figure><p><a href="https://www.telegraph.co.uk/news/2018/03/12/jamie-carragher-apologises-spitting-incident-moment-madness/">Apologising for spitting</a> towards a teenage girl and her father in a car, football pundit Jamie Carragher referred to a “moment of madness”. It was, he said, like an “out of body” experience, which had taken over for a few seconds following a <a href="http://www.skysports.com/football/man-utd-vs-liverpool/373392">football match</a> between his old club Liverpool and Manchester United. </p>
<p>So what makes certain people more prone to moments of aggressive behaviour? And how can we better manage those moments? To accurately answer these questions, we need to distinguish between <a href="https://www.tandfonline.com/doi/abs/10.1080/17405620444000300?src=recsys&journalCode=pedp20">two different types of aggression</a>.</p>
<p>The first is what psychologists refer to as “proactive aggression”. This is a deliberate, purposeful attack on a victim. Proactive aggression is often associated with callousness and a lack of remorse or guilt. </p>
<p>The second type, “reactive aggression” is an impulsive response under conditions of stress or anger. It is a response to provocation, frustration or threat, and involves enraged attacks, usually directed at the source. </p>
<p>Examples of reactive aggression might include so-called crimes of passion or road rage – and Carragher’s response to the actions of a football fan on the motorway. Such aggressive outbursts are often followed by a sense of shame and regret, which makes them different to proactive aggression. </p>
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<p>The brain mechanisms underpinning reactive aggression also differ, as seen <a href="http://www.journalofpsychiatricresearch.com/article/S0022-3956(16)30069-3/fulltext">in a study</a> of intermittent explosive disorder (IED). IED is a behavioural disorder characterised by disproportionate outbursts of anger and violence. </p>
<p>For the study, individuals with IED underwent an MRI brain scan while observing pictures of faces with various emotional expressions (angry, sad, happy, frightened) to observe how the amygdala (an almond-shaped structure in the brain behind the temples) responded. </p>
<p>The amygdala tends to activate when we feel threatened or fearful, but is also important for responding with empathy to emotions in other people. Under normal circumstances, we inhibit aggressive behaviour because we empathise with the pain it might cause victims. </p>
<p>In the study, participants with IED showed a much greater amygdala reaction in the left side of the brain in response to angry faces (a threat) than those who did not have IED. The degree of reaction was also linked to the number of serious aggressive outbursts the person had engaged in throughout their lifetime. </p>
<p>In addition, for those with IED, communication between the amygdala and an area at the front of the brain (the orbitofrontal cortex) was impaired. The orbitofrontal cortex helps to integrate emotions and social context in order to activate situation-appropriate behaviours. The frontal lobes affect our ability to monitor, plan and regulate behaviours and emotions – our self-control. </p>
<p>If the amygdala is too highly activated, it can override the function of regions involved in monitoring and regulating behaviour, leading to the experience of “blind rage”. Poor emotional control (frontal function) is associated with an increased tendency towards reactive aggressive behaviour. </p>
<p>Overly rigid control over emotions can also present difficulties by impairing the healthy processing of feelings. Under continued conditions of stress, at some stage, a person will reach breaking point. Although the outbursts might be less frequent, the rage experienced is often more severe. </p>
<p>The accumulation of intense over-controlled emotions due to chronic stress and continued provocation can make a person vulnerable to intermittent, but severe explosive reactions. People in high pressure situations where emotional control is required (such as athletes, politicians or surgeons) may be particularly vulnerable, and might consider taking specific steps to reduce the risk. </p>
<h2>Anger management</h2>
<p>There are several innovative ways in which people can build psychological resilience and regulate behaviour. These include brain training, meditation and nutrition, which can alter the way emotions are experienced or perceived. Mindfulness meditation, for example, <a href="https://link.springer.com/article/10.1007/s12671-012-0191-5">has been shown</a> to help in the regulation depression, anxiety and anger. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/210805/original/file-20180316-104673-1e4294e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/210805/original/file-20180316-104673-1e4294e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210805/original/file-20180316-104673-1e4294e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210805/original/file-20180316-104673-1e4294e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210805/original/file-20180316-104673-1e4294e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210805/original/file-20180316-104673-1e4294e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210805/original/file-20180316-104673-1e4294e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Reducing aggression in a tin.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/can-sardines-746391478?src=rKY3xbYIqn7bpqu3IiKR3g-1-0">Shutterstock</a></span>
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<p>Other methods directly address the body’s physiological response to stress, when steroid hormones (like cortisol) and inflammatory chemicals are released in the body. These can damage the body and brain, and interfere with the modulation of emotion and behaviour by <a href="http://news.berkeley.edu/2014/02/11/chronic-stress-predisposes-brain-to-mental-illness/">disrupting and damaging</a> functions of the frontal lobe and its connections with other areas of the brain. </p>
<p>This is in part controlled by our “second brain” – the gut. Work from our lab suggests the bacteria in our intestines plays a part in modulating feelings by affecting the release of these chemicals. </p>
<p><a href="https://ntupsychology.onlinesurveys.ac.uk/gut-feeling-is-your-mood-influenced-by-your-gut">Collaborative work</a> between Nottingham Trent University and the University of Reading is now looking into how the bacteria in our intestines is linked to brain function, and how we feel about ourselves and others.</p>
<p>What we eat has an impact on how we behave. Certain nutrients protect against these adverse effects – for example, those contained in fish or tumeric, a powerful anti-inflammatory. </p>
<p>Some studies suggest dietary supplementation with fish oil and other micronutrients <a href="http://irep.ntu.ac.uk/id/eprint/28028/1/Dean.Fido-2015.pdf">can improve</a> frontal lobe function and reduce aggressive behaviour. </p>
<p>Perhaps football stadium food stalls should start selling sardines.</p><img src="https://counter.theconversation.com/content/93320/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Sumich is affiliated with Nottingham Trent University (NTU), UK and Auckland University of Technology (AUT), NZ. He has previously received funding from BIAL foundation, The Mother and Child Foundation, Equazen, Crystal Mind, NTU, AUT, Royal Society of New Zealand. </span></em></p>Jamie Carragher blamed a moment of madness for spitting at car passengers. But where do these moments come from?Alexander Sumich, Associate Professor of Psychology, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/925012018-03-01T19:19:28Z2018-03-01T19:19:28ZYes the ‘cheerleader effect’ is real – and you can make it work in your favour<figure><img src="https://images.theconversation.com/files/208198/original/file-20180228-36696-8kx1s3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Harsh truth: you probably look more attractive in a group than on your own. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-adult-female-friends-taking-group-1033405615?src=PoDVrdP_5pkM6fvHpCrp-Q-1-1">from www.shutterstock.com </a></span></figcaption></figure><p>When it comes to presenting yourself online – such as your profile pic for Facebook or even Tinder – which type of photo do you chose? The selfie you’ve taken after careful consideration of lighting, hair and maybe makeup? (No doubt, you look great!) Or the group photo with friends, possibly less styled, but that captures a moment among peers?</p>
<p>It might come as a surprise that it’s the group photo will make you look more attractive – it’s a phenomenon known as the “cheerleader effect”. </p>
<p>The cheerleader effect is real, but perhaps not for the reasons you think. The group shot with friends may indeed communicate you are sociable and friendly, but this is not what is making you more attractive. </p>
<p>The real explanation boils down to how human brains deal with information. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/women-troll-on-dating-apps-just-as-often-as-men-72736">Women troll on dating apps just as often as men</a>
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</em>
</p>
<hr>
<h2>Give me an E! For evidence</h2>
<p>First popularised by the television series <a href="https://en.wikipedia.org/wiki/How_I_Met_Your_Mother">How I Met Your Mother</a>, the character Barney Stinson uses the term cheerleader effect to <a href="https://www.youtube.com/watch?v=qDzkMXpDZfc">describe a woman</a> appearing attractive when in a group, but not as an individual. </p>
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<img alt="" src="https://images.theconversation.com/files/208237/original/file-20180228-36689-qq09f5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/208237/original/file-20180228-36689-qq09f5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/208237/original/file-20180228-36689-qq09f5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/208237/original/file-20180228-36689-qq09f5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/208237/original/file-20180228-36689-qq09f5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/208237/original/file-20180228-36689-qq09f5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/208237/original/file-20180228-36689-qq09f5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Cheerleaders like to hang out in groups.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/dwilliss/7915861296/in/photolist-d4uRMb-5ZTMxJ-anVqfM-X91xcM-X5tks5-22g1a-EbYcEx-dAN7dJ-Mso43-2j37wt-yok4Ce-dAN7bw-5g7bwG-6Q8Jxx-dwRzZT-7pSRYs-6hNWoA-8J26hh-7pSTqq-qTihok-9Za2GS-7pNUSi-agkJJb-7pNSJP-8AUiw7-r89Nnm-cUWRvy-7pNTYg-8LSrwk-b7bVHD-dwWPyY-7cgnLg-4YHDS8-WxvzMd-cJj9R-6swruZ-6i8QN1-dAGDaR-apZc7Z-22g3r-nueZKs-aq2Tby-8ATCr8-apZcbc-dsBn1H-eJ6q3c-uzEmx-8WVrg6-nueZso-6ie8a1">dwilliss/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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</figure>
<p>His interpretation was typical of American sitcoms, but Barney’s comments are founded in research. </p>
<p>In 2003, scientific evidence of the cheerleader effect was <a href="http://journals.sagepub.com/doi/abs/10.1177/0956797613497969">published</a> in a paper where across five studies, both males and females were rated more attractive when presented as part of a group photo compared to a solo photo. The authors, Drew Walker and Edward Vul, presented 130 participants with group photographs containing three female faces or three male faces. Each face was then cropped from the photograph and presented individually. </p>
<p>Participants rated the attractiveness of faces presented in a group and individually. Regardless of gender, attractiveness ratings were higher when people were presented in a group compared to presented individually.</p>
<p>However, this does not mean the bigger the group - the more attractive you are. The authors found that group size, whether 4, 9, or 16 individuals, had no effect on attractiveness ratings. Basically, a handful of friends is all you need to take advantage of this effect.</p>
<p>Importantly, studies have shown the cheerleader effect to be reliable. Additional studies published in <a href="http://journals.sagepub.com/doi/10.1177/0146167215572799">2015</a> and one just <a href="https://www.nature.com/articles/s41598-018-20784-5">this month</a> continue to find a groups’ attractiveness is significantly higher than the attractiveness of an individual group member. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/208225/original/file-20180228-36686-14znbzk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/208225/original/file-20180228-36686-14znbzk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=791&fit=crop&dpr=1 600w, https://images.theconversation.com/files/208225/original/file-20180228-36686-14znbzk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=791&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/208225/original/file-20180228-36686-14znbzk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=791&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/208225/original/file-20180228-36686-14znbzk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=994&fit=crop&dpr=1 754w, https://images.theconversation.com/files/208225/original/file-20180228-36686-14znbzk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=994&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/208225/original/file-20180228-36686-14znbzk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=994&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Studies exploring the cheerleader effect ask study participants to rank attractiveness of different individuals alone or with other people.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41598-018-20784-5">Daniel J. Carragher, Blake J. Lawrence, Nicole A. Thomas & Michael E. R. Nicholls</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>Give me a B! For brain</h2>
<p>The robustness of the cheerleader effect is best explained by looking at how your brain works, and understanding perception. </p>
<p>Humans tend not to process every individual detail they perceive in their environment. Instead of devoting significant attention to all individual characteristics, our brain quickly <a href="http://www.cell.com/trends/cognitive-sciences/fulltext/S1364-6613(11)00004-0">summarises the information as a group</a>. Evidence even suggests that our brains may be <a href="https://www.scientificamerican.com/article/wired-for-categorization/">wired for such categorisation</a>. </p>
<p>Grouping perceptual information has a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC33948/">distinct evolutionary advantage</a>, enhancing survival by <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3659333/">reducing perceptual load</a> (the burden of interpreting a scene from visual information). </p>
<p>This perceptual effect is best demonstrated with the <a href="http://www.illusionsindex.org/ir/ebbinghaus-illusion">Ebbinghaus Illusion</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/208194/original/file-20180227-36671-qd7vfp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/208194/original/file-20180227-36671-qd7vfp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/208194/original/file-20180227-36671-qd7vfp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/208194/original/file-20180227-36671-qd7vfp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/208194/original/file-20180227-36671-qd7vfp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/208194/original/file-20180227-36671-qd7vfp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/208194/original/file-20180227-36671-qd7vfp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Ebbinghaus Illusion: the two blue circles are exactly the same size - however, the one on the right appears larger.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/ebbinghaus-illusion-titchener-circles-optical-relative-456478144?src=ry6aGDt0zWYIkpPxPd7gqA-1-0">from www.shutterstock.com</a></span>
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<p>In this illusion, the inside circles are identical in size, yet the surrounding information (i.e., surrounding circles) alters our perception. Here, rather than focusing on the individual characteristics of the inside circles, our perception is altered by the group information. This is known as <a href="http://cognitivepsychology.wikidot.com/cognition:topdown">top-down processing</a>, where the whole element is perceived before individual characteristics. This is in contrast to bottom-up processing, where there is progression from the individual characteristics to the whole.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/three-visual-illusions-that-reveal-the-hidden-workings-of-the-brain-80875">Three visual illusions that reveal the hidden workings of the brain</a>
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</em>
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<p>The same characteristics of this illusion extend to the cheerleader effect. In this effect, rather than attend to individual characteristics, we focus on the group as a whole.</p>
<p>Such an effect can even be applied to explain social biases. <a href="http://psycnet.apa.org/record/1997-97264-007">Social categorisation</a> is the process of mentally categorising individuals into groups based on characteristics such as age, sex, and ethnicity. This quick categorisation of social information <a href="https://www.verywellmind.com/what-is-prejudice-2795476">promotes fast social interactions</a> - but has some serious and broader consequences. </p>
<h2>Give me a D! For dating</h2>
<p>The evidence suggests that presenting yourself with a group will tend to average out any “unattractive” individual characteristics. So, how can you use this information to your advantage? </p>
<p>Well, you can apply this information when selecting a profile picture. Perhaps you’re seeing someone new, and suspect they could be doing a little Facebook research on you. Select a profile picture of you and a few friends for maximum attractiveness. Bonus - group pictures can also demonstrate that <a href="https://www.sciencedirect.com/science/article/pii/S0747563213000046">you’re social</a>.</p>
<p>Maybe you’re heading out to the pub to meet the local singles? Don’t forget your “wing” men/women (ideally a group of 4!). </p>
<p>And if you’re online dating, how about including some pictures of you and a few friends in your profile? However, remember to label yourself in the photo to avoid users finding your group photo attractive but moving on because they can’t figure out who in the photo you are. </p>
<h2>Give me a B! For Barney</h2>
<p>You might not agree with everything Barney Stinson says, but on the question of the cheerleader effect he was broadly right. </p>
<p><img width="70%" src="https://media.giphy.com/media/vTxWtmX2b0oH6/giphy.gif"></p><img src="https://counter.theconversation.com/content/92501/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Evita March does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The cheerleader effect describes the phenomenon that you appear more attractive in a group than solo - and it works for men as well as women.Evita March, Lecturer of Psychology, Federation University AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/813472017-12-20T13:22:48Z2017-12-20T13:22:48ZWhy most of us lean to the right when we kiss<figure><img src="https://images.theconversation.com/files/200193/original/file-20171220-4957-ot704f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://theconversation.com/drafts/81347/edit">Shutterstock</a></span></figcaption></figure><p>Your brain is an organ of two halves – the left side and the right side. And there are many brain functions, such as language skills or which hand you write with, which are organised mostly in one side of the brain or the other. </p>
<p>Simple behavioural tests have now allowed us to see how this organisation is revealed through biases in how we see and interact with the world – and each other – often without us being aware of it. </p>
<p>Examining how people perceive a diagram of <a href="https://www.ncbi.nlm.nih.gov/pubmed/21228922">variously orientated lines</a> and angles provided clues that people typically have a subconscious bias for seeing things set out in clockwise orientations. </p>
<p>We then realised that this might also be related to a number of physical instincts that people have, such as which way they turn their heads. After looking at <a href="https://www.ncbi.nlm.nih.gov/pubmed/27350096">recent research</a> in visual psychophysics and visual neuroscience, we saw various perceptual and behavioral phenomena in which humans can have a directional bias.</p>
<p>Many of these turning behaviours are seen early in life. For example, infants have an initial bias for turning the head to the right (and consequently extending the left arm outward to compensate for that movement). </p>
<p>Some <a href="https://www.nature.com/articles/421711a">previous research</a> found that such an instinctive turn to the right extends to adulthood – when an adult kisses another on the lips, their heads tend to automatically lean to the right. But is this an extension of the bias that humans are born with, or do people simply learn to kiss that way? </p>
<p>In Western societies it is commonplace to see people kiss in public, on television, and in films. But are these screen kisses reflecting society, or do they influence how people behave? The prior research on the subject was all conducted with kissing in what are known as “W.E.I.R.D.” – Western, Educated, Industrialized, Rich and Democratic – societies. So the conclusions might not reflect what humans naturally do in the absence of learning through observation. </p>
<p>Bangladesh seemed like an interesting non-W.E.I.R.D. country to examine this. It is a conservative Muslim country where kissing is prohibited in public, and even censored from television or films. So, whereas similar results from the W.E.I.R.D. countries could be attributed to social learning or socio-cultural factors, the same cannot as easily be said in Bangladesh. </p>
<p>In our study, we asked a number of married couples in Bangladesh to kiss privately in their own homes. They then went into separate rooms to report on various aspects of the kiss independently of each partner. </p>
<h2>A kiss is still a kiss</h2>
<p>The <a href="https://www.nature.com/articles/s41598-017-04942-9">results</a> showed that more than two thirds of the kissing individuals had a bias for turning their heads to the right. When initiating a kissing “move” (men were 15 times more likely to initiate the kiss) right-handed people leaned right and left-handed people leaned left. </p>
<p>The person being kissed, regardless of whether they were left or right handed, responded by matching the partners’ head leaning direction. It felt awkward to go the other way as reported by most of the kiss recipients and kiss initiators in our study. </p>
<p>It turns out that humans are similar, even if our social values, and the habits we are exposed to, differ. This bias in the act of kissing is likely innate and determined by the brain splitting up tasks to its different hemispheres, similar to being either right- or left-handed. It is perhaps specifically concerned with the functions in the left cerebral hemisphere, located in the emotion and decision-related areas of the brain.</p>
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<p>Different hormone levels (such as testosterone) in each hemisphere and neurotransmitters might be unevenly distributed to each hemisphere (such as dopamine, involved in reward behaviours) and give rise to a bias to turn right.</p>
<p>If you do lean in for a kiss to the left, you may be in the minority. But don’t worry – if the person you are kissing wants to be kissed, they will likely go left, too.</p><img src="https://counter.theconversation.com/content/81347/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Activity in the left hand side of the brain, specifically in areas of emotion, could explain why most people lean to the right before lips smack.Michael J. Proulx, Senior Lecturer in Psychology, University of BathA.K.M. Rezaul Karim, Professor of Psychology, University of DhakaAlexandra A. de Sousa, Senior Lecturer in Psychology, Bath Spa UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/837162017-09-24T20:03:21Z2017-09-24T20:03:21ZI’ve always wondered: can animals be left- and right-pawed?<figure><img src="https://images.theconversation.com/files/186153/original/file-20170915-16298-1p6agw1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Southpaws seem to be more common among cats and dogs than humans.</span> <span class="attribution"><span class="source">Eric Isselee/Shutterstock.com</span></span></figcaption></figure><p><em>This is an article from I’ve Always Wondered, a series where readers send in questions they’d like an expert to answer. Send your question to alwayswondered@theconversation.edu.au</em></p>
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<p><strong>While watching my cat engaging in yet another battle with my shoelace, I noticed that he seemed mainly to use his left front paw. Do animals have a more dextrous side that they favour for particular tasks, just like humans? – Mike, Perth.</strong></p>
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<hr>
<p>The short answer is: yes they do! Like humans, many animals tend to use one side of the body more than the other. This innate handedness (or footedness) is called behavioural or motor laterality. </p>
<p>The term laterality also refers to the primary use of the left or right hemispheres of the brain. The two halves of the animal brain are <a href="http://www.rightleftrightwrong.com/brain.html">not exactly alike</a>, and each hemisphere differs in function and anatomy. In general terms, the left hemisphere controls the right side of the body and the right hemisphere controls the left side. </p>
<p>Laterality is an ancient inherited characteristic and is widespread in the animal kingdom, in both vertebrates and invertebrates. Many <a href="http://www.rightleftrightwrong.com/theories.html">competing theories</a> (neurological, biological, genetic, ecological, social and environmental) have been proposed to explain how the phenomenon developed, but it remains largely a mystery. </p>
<h2>Animal ‘handedness’</h2>
<p>Humans tend to be right-handed. Lefties or “southpaws” make up <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3927078/">only about 10% of the human population</a>, and <a href="http://psycnet.apa.org/doiLanding?doi=10.1037/a0012814">more males than females are left-handed</a>.</p>
<p>Great apes show <a href="http://www.sciencedirect.com/science/article/pii/S0166432812006237?via%3Dihub">similar handedness patterns</a> to humans. Most chimps, for instance, <a href="http://video.nationalgeographic.com/video/news/chimps-right-hand-vin?source=relatedvideo">seem to be right-handed</a>. But not many studies have looked at laterality in non-primate animals. </p>
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<strong>
Read more:
<a href="https://theconversation.com/why-are-most-people-right-handed-the-answer-may-be-in-the-mouths-of-our-ancestors-69712">Why are most people right handed? The answer may be in the mouths of our ancestors</a>
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<p>There is some evidence to suggest that <a href="http://www.sciencedirect.com/science/article/pii/S0376635702001614?via%3Dihub">dogs</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/2265897">cats</a> can be right- or left-pawed, although the ratio seems to be more evenly split than in humans, and it is unclear whether there are sex differences. </p>
<p>If you’re a pet owner you can <a href="http://www.dailymail.co.uk/news/article-2195039/Is-pet-right-left-handed-The-test-uses-cheese-sofas-backdoor-out.html">do an experiment for yourself</a>. Which paw does your cat or dog lead with when reaching out for something, or to tap open a pet door?</p>
<p>To test your pet dog, you can place a treat-filled <a href="https://www.kongcompany.com/en-au/kong-101/kong-101/">Kong toy</a> directly in front of your dog and see which paw he or she uses to hold it to get the food out. A dog may use either paw or both paws.</p>
<p>To test your pet cat, you can set a “food puzzle” by putting a treat inside a glass jar and watching to see which paw your cat uses. Don’t forget to repeat it lots of times and take notes to see whether the effect is real or just random chance!</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/ykb46flx47c?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Don’t forget to repeat the experiment lots of times.</span></figcaption>
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<p>Horses also seem to <a href="http://www.equinescienceupdate.co.uk/mslat.htm">prefer to circle in one direction rather than the other</a>. Meanwhile, one study suggests that <a href="http://news.nationalgeographic.com/2015/06/150618-kangaroos-evolution-animals-science/">kangaroos are almost exclusively lefties</a>, although the neural basis for this is unknown. </p>
<h2>Lateralisation and brain function</h2>
<p>In humans, the left hemisphere is mainly associated with <a href="https://www.sciencedaily.com/releases/2014/07/140704134633.htm">analytical processes and language</a> and the right hemisphere with orientation, awareness and musical abilities, although this dichotomy is simplistic at best.</p>
<p>Is there evidence of lateralised brain function in non-human animals too? A team of Italian researchers think so. They found that dogs <a href="http://www.cell.com/current-biology/pdf/S0960-9822%2807%2900949-9.pdf">wag their tails to the right</a> when they see something they want to approach, and to the left when confronted with something they would rather avoid. This suggests that, just as for people, the right and left halves of the brain do different jobs in controlling emotions.</p>
<p>Laterality is also connected to the direction in which hair grows (so-called stuctural laterality), or even to the senses (sensory laterality). Many animals use they left eye and left ear (indicating right brain activation) more often than the right ones when <a href="http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0184933&type=printable">investigating objects that are potentially frightening</a>. However, asymmetries in olfactory processing (nostril use) are less well understood. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/186158/original/file-20170915-16320-1o2xq1r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/186158/original/file-20170915-16320-1o2xq1r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/186158/original/file-20170915-16320-1o2xq1r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/186158/original/file-20170915-16320-1o2xq1r.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/186158/original/file-20170915-16320-1o2xq1r.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/186158/original/file-20170915-16320-1o2xq1r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/186158/original/file-20170915-16320-1o2xq1r.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/186158/original/file-20170915-16320-1o2xq1r.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Research suggests most kangaroos are southpaws.</span>
<span class="attribution"><span class="source">Ester Inbar/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The left or right bias in sensory laterality is separate from that of motor laterality (or handedness). However, some researchers think that side preference is linked to the direction of hair whorls (“cow licks”), which can grow in a clockwise or anticlockwise direction. More right-handed people have a <a href="https://www.ncbi.nlm.nih.gov/pubmed/14504234">clockwise hair pattern</a>, although it is <a href="http://doctorbarkman.blogspot.com.au/2013/10/can-canine-hair-whorls-predict.html">unclear if this is true of other animals</a>. </p>
<p>The direction of hair growth and handedness are also related to temperament. Left-handed people might be <a href="http://onlinelibrary.wiley.com/doi/10.1002/jts.20222/pdf">more vulnerable to stress</a>, as are <a href="https://www.ncbi.nlm.nih.gov/pubmed/16893254">left-pawed dogs</a> and many other animals. In general, many animals, including humans, that have a clockwise hair whorl are less stress-prone than those with anticlockwise hair growth. The position of the hair whorl also matters; cattle and horses with hair whorls directly above the eyes are <a href="http://www.j-evs.com/article/S0737-0806%2815%2930055-1/pdf">more typically difficult to handle than those with whorls lower down on the face</a>. </p>
<p>Elsewhere in the animal kingdom, snails also have a form of laterality, despite having a very different nervous system to vertebrates like us. Their shells spiral in either a “right-handed” or “left-handed” direction – a form of physical asymmetry called “chirality”. This chirality is <a href="https://phys.org/news/2009-11-rightleft-handedness-snails-lab.html">inherited</a> – snails <a href="http://jeb.biologists.org/content/213/5/v.2">can only mate with matching snails</a>.</p>
<p>Chirality is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692985/">even seen in plants</a>, depending on the asymmetry of their leaves, and the direction in which they grow.</p>
<p>As an aside, left-handedness has been discriminated against in many cultures for centuries. The Latin word <em>sinistra</em> originally meant “left” but its English descendant “sinister” has taken on meanings of evil or malevolence. The word “right”, meanwhile, connotes correctness, suitability and propriety. Many everyday objects, from scissors to notebooks to <a href="https://plus.google.com/+Vi0letAshes/posts/88cRFZbqZX4">can-openers</a>, are designed for right-handed people, and the Latin word for right, <em>dexter</em>, has given us the modern word “dextrous”.</p>
<h2>Why is the brain lateralised?</h2>
<p>One adaptive advantage of lateralisation is that individuals can perform two tasks at the same time if those tasks are governed by opposite brain hemispheres. Another advantage might be resistance to disease – hand preference in animals is associated with differences in immune function, with <a href="https://www.ncbi.nlm.nih.gov/pubmed/15265650">right-handed animals mounting a better immune response</a>.</p>
<p>Does it matter if your cat, dog, horse or cow favours one paw (or hoof) over another? Determining laterality – or which side of the brain dominates the other – could change the way domestic animals are bred, raised, <a href="http://www.abc.net.au/catalyst/stories/3465535.htm">trained and used</a>, including predicting which puppies will make the best <a href="http://www.sciencedirect.com/science/article/pii/S1090023311003649?via%3Dihub">service dogs</a>, and which racehorses will <a href="http://www.equinescienceupdate.co.uk/mslat.htm">race better on left- or right-curving tracks</a>. </p>
<p>And even if your dog or cat never clutches a pen, or uses one limb more than the other, just be grateful that they haven’t yet developed opposable thumbs!</p>
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<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/186157/original/file-20170915-16324-19041s6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/186157/original/file-20170915-16324-19041s6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/186157/original/file-20170915-16324-19041s6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/186157/original/file-20170915-16324-19041s6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/186157/original/file-20170915-16324-19041s6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/186157/original/file-20170915-16324-19041s6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/186157/original/file-20170915-16324-19041s6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><em>This article is dedicated to the memory of Bollo the cat, who inspired this question but has since passed away.</em></p><img src="https://counter.theconversation.com/content/83716/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The animal kingdom is full of lefties and righties, although rarely is the ratio skewed as much as it is in humans. If you’re wondering about your own pet, you can find out with a simple experiment.Janice Lloyd, Senior Lecturer in Veterinary Behaviour, Welfare & Ethics, James Cook UniversityRichard Squires, Associate Professor of Companion Animal Medicine, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/811502017-08-09T14:52:51Z2017-08-09T14:52:51ZHow reducing the number of stressful events in our lives could help beat dementia<figure><img src="https://images.theconversation.com/files/181348/original/file-20170808-22953-hajvq8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Matters of the mind.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-portrait-sad-young-woman-man-454284454">Shutterstock</a></span></figcaption></figure><p>Stress is bad for our physical and mental health. It has been linked to several leading causes of death, including <a href="http://heart.bmj.com/content/heartjnl/early/2017/06/01/heartjnl-2017-311610.full.pdf">heart disease</a> and mood disorders, such as <a href="http://www.sciencedirect.com/science/article/pii/S0006322312005604">depression</a>.</p>
<p>Now <a href="https://www.theguardian.com/society/2017/jul/16/stressful-experiences-can-age-brain-by-years-alzheimers-experts-hear">new research</a> suggests that the actual number of stressful experiences we encounter can have dramatic consequences for the health of our brains. </p>
<p>In all, 27 events were identified as being particularly detrimental. These include being expelled from school during adolescence and experiencing unemployment as an adult.</p>
<p>Each instance of stress was said to age the brain by an average of 1.5 years. So exposure to a handful could set you back a decade in terms of cognition. </p>
<p>The research identifying the 27 events was presented at the <a href="https://www.alzheimers.org.uk/news/article/222/alzheimer_s_association_international_conference_aaic_2017">Alzheimer’s Association International Conference</a> in London in July 2017. A group from the <a href="http://www.med.wisc.edu/news-events/alzheimers-research-presented-at-international-conference-in-london/51171">School of Medicine and Public Health</a> at the University of Wisconsin-Madison asked 1,320 people to remember the stressful events that had occurred across their lifespans and then complete a number of tasks to assess their thinking skills. These included tests related to various aspects of memory – known to deteriorate with age – such as the ability to accurately recall details from a story.</p>
<p>Participants who had experienced a greater number of stressful events were found to score poorly at these tasks, indicating a loss of cognitive function. </p>
<p>Linking these findings to dementia could undoubtedly help identify those most susceptible to developing neurodegenerative conditions – and lead to potential risk reducing interventions, designed to modify the effects of stress. </p>
<p>But is the onset of something as complex as <a href="https://www.alzheimers.org.uk/info/20007/types_of_dementia/2/alzheimers_disease">Alzheimer’s disease</a> likely to come down to a simple numbers game, in which one too many stressful events mean it’s game over?</p>
<h2>Stress and the ageing brain</h2>
<p>Reductions in the efficiency of our memory and thinking skills are a <a href="http://europepmc.org/articles/pmc3800175">natural part of ageing</a>. As the years pass, we lose brain tissue and cannot support cognitive functions as readily as in our youth. </p>
<p>But exposure to stressful episodes could feasibly speed up this process, producing accelerated or more pronounced decline. Those who took part in the study were on average only 58 years of age, yet there was already noticeable variation in their cognition on the basis of different stress levels. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/181349/original/file-20170808-22945-1h4jygu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/181349/original/file-20170808-22945-1h4jygu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/181349/original/file-20170808-22945-1h4jygu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/181349/original/file-20170808-22945-1h4jygu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/181349/original/file-20170808-22945-1h4jygu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/181349/original/file-20170808-22945-1h4jygu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/181349/original/file-20170808-22945-1h4jygu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Turn it down.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<p>While <a href="http://www.sciencedirect.com/science/article/pii/S1552526015029143">anxiety,</a> <a href="http://www.sciencedirect.com/science/article/pii/S0091302215300108">depression</a> and <a href="http://jamanetwork.com/journals/jamaneurology/article-abstract/1653649">poor cerebrovascular health</a> have been identified as potential risk factors for dementia, declines in cognition can occur for a variety of reasons.</p>
<p>Prolonged exposure to stress, which would be expected from the loss of a parent or having a child involved in a serious accident, leads to long-term alterations in the body’s response to adverse events – involving the hormone cortisol.</p>
<p>Chronic over-production of <a href="https://en.wikipedia.org/wiki/Cortisol">cortisol</a> has a negative effect on regulatory systems responsible for mood, blood pressure, and immune system function. It also inhibits memory formation and learning in key brain regions such as the <a href="http://www.sciencedirect.com/science/article/pii/S0006322314003515">hippocampus</a>, which is particularly affected in Alzheimer’s. </p>
<h2>Mediating factors</h2>
<p>There is likely a <a href="http://www.alzheimersresearchuk.org/about-dementia/types-of-dementia/alzheimers-disease/risk-factors/">complex interaction</a> between biological factors and our experiences, encompassing not only stress but also how mentally active we are, our nutrition, and exercise habits. </p>
<p>Lifestyle factors may provide a buffer against resulting brain damage, and support how the brain adapts to the challenge of ageing. This concept, known as “<a href="http://www.sciencedirect.com/science/article/pii/S1474442212701916">cognitive reserve</a>”, explains why some people are more or less susceptible to the effects of stress.</p>
<p>Cognitive reserve defines brain function as something we have some control over – to shape our life course and maintain our thinking skills. This is surely welcome news in a world where exposure to stress seems unavoidable. </p>
<p>On the other hand, those less able to adopt positive choices appear to be the <a href="http://journals.sagepub.com/doi/abs/10.1177/002214650504600206">hardest hit</a>. The researchers who highlighted the 27 events also found that the effects of stress were <a href="https://www.theguardian.com/society/2017/jul/16/stressful-experiences-can-age-brain-by-years-alzheimers-experts-hear">more profound in the African American population</a>, who experienced 60% more stressful life events than their Caucasian counterparts. </p>
<p>With each life event adding years to their cognitive ability, this highlights the need for support in managing the potentially devastating consequences of stress on the body and the brain – particularly among the most vulnerable.</p><img src="https://counter.theconversation.com/content/81150/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Claire J. Hanley does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Tough events are tough on the brain.Claire J. Hanley, Lecturer in Cognitive Neuroscience & Ageing, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/758472017-06-01T20:13:50Z2017-06-01T20:13:50ZWhat causes Alzheimer’s disease? What we know, don’t know and suspect<figure><img src="https://images.theconversation.com/files/171067/original/file-20170525-23232-1rvtxjj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A hallmark of Alzheimer's disease is gradual deterioration of memory.</span> <span class="attribution"><a class="source" href="https://unsplash.com/search/memories?photo=7sPg5OLfExc">Roman Kraft/Unsplash</a></span></figcaption></figure><p><em>This is a long read.</em></p>
<hr>
<p>Alzheimer’s disease is the most common form of dementia, which is an <a href="https://www.fightdementia.org.au/about-dementia/what-is-dementia">umbrella term</a> used to describe general loss of memory, thinking skills and other day-to-day functions (such as cooking, paying bills, cleaning and even dressing). </p>
<p>A hallmark of <a href="https://www.fightdementia.org.au/about-dementia/types-of-dementia/alzheimers-disease">Alzheimer’s disease</a> is gradual deterioration of memory. But it is a biological disease, which means that, besides seeing outwards symptoms such as memory loss, we can also measure the breakdown that occurs in the brain as a consequence of disease progression.</p>
<p>Alzheimer’s is identified by the presence of two proteins in the brain, known as <a href="http://www.alz.org/braintour/plaques.asp">amyloid</a> and <a href="http://www.alz.org/braintour/tangles.asp">tau</a>. Amyloid proteins <a href="http://www.nature.com/nrm/journal/v15/n6/fig_tab/nrm3810_T1.html">aggregate into sticky clumps</a> called “plaques”. And tau proteins tend to form “tangles”. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/171073/original/file-20170525-23234-2af3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171073/original/file-20170525-23234-2af3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/171073/original/file-20170525-23234-2af3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=773&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171073/original/file-20170525-23234-2af3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=773&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171073/original/file-20170525-23234-2af3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=773&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171073/original/file-20170525-23234-2af3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=972&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171073/original/file-20170525-23234-2af3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=972&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171073/original/file-20170525-23234-2af3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=972&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dementia is an umbrella term used to describe general loss of memory, thinking skills and other day-to-day functions.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>While it is still unclear how amyloid and tau interact to cause the disease, these plaques and tangles seem to <a href="https://www.nia.nih.gov/alzheimers/publication/2011-2012-alzheimers-disease-progress-report/primer-alzheimers-disease-and">play a role in blocking messages</a> between brain cells. They induce inflammation wherever they accumulate, and may gum up the transportation system that helps clear the brain of debris.</p>
<p>Ultimately, the disease causes the death of brain cells. This results in an overall <a href="http://www.alzforum.org/news/research-news/brain-changes-speak-volumes-about-normal-aging-and-dementia">shrinking of brains</a> of patients with Alzheimer’s disease. Currently, while people can be diagnosed with <em>probable</em> Alzheimer’s disease, a <a href="http://www.alz.org/professionals_and_researchers_diagnosing_alzheimers.asp">reliable diagnosis</a> can only be made postmortem by searching for the tau and amyloid proteins. </p>
<p>Brain imaging techniques mean we can determine levels of these proteins in people who are still alive. However, while abnormal levels of the proteins in a healthy brain can increase the chances of developing Alzheimer’s disease, <a href="https://www.theatlantic.com/health/archive/2017/02/alzheimers-amyloid-hypothesis/517185/">this outcome is not always guaranteed</a>.</p>
<h2>Amyloid and tau</h2>
<p>Knowing the biology and mechanisms behind the genesis of Alzheimer’s disease is <a href="https://www.scientificamerican.com/article/why-alzheimer-s-drugs-keep-failing/">critical for the success</a> of future <a href="https://www.fightdementia.org.au/research/trials">clinical trials</a>. </p>
<p>The accumulation of amyloid protein in the brain is mainly found in Alzheimer’s disease, along with the way it spreads. Around 30% of healthy adults aged over 60 have high amyloid concentrations in their brain. It <a href="https://www.ncbi.nlm.nih.gov/pubmed/23477989">takes about 20 years</a> before people in this group start to display dementia symptoms such as memory loss. </p>
<p><a href="http://www.sciencemag.org/news/2016/05/tau-protein-not-amyloid-may-be-key-driver-alzheimer-s-symptoms">Tau</a>, on the other hand, is found across a wide range of conditions. These include Alzheimer’s disease, <a href="http://www.alz.org/dementia/chronic-traumatic-encephalopathy-cte-symptoms.asp">chronic traumatic encephalopathy</a> (a neurodegenerative disease linked to repetitive concussions and brain trauma), <a href="https://ghr.nlm.nih.gov/condition/niemann-pick-disease">Niemann-Pick</a> disease (a heritable disease that affects fat metabolism in cells) and <a href="http://www.alz.org/dementia/down-syndrome-alzheimers-symptoms.asp">Down Syndrome</a>. </p>
<p>Animal studies suggest a range of <a href="http://www.alzforum.org/news/research-news/more-evidence-distinct-tau-strains-may-cause-different-tauopathies">tau “strains”</a> exist, like “<a href="http://www.iflscience.com/health-and-medicine/new-prion-disease-raises-questions-about-whether-alzheimer-s-and-parkinson-s/">prions</a>”. Prions are small, infectious and <a href="http://memory.ucsf.edu/cjd/overview/prions">abnormally twisted (or misfolded) proteins</a> that can affect the brain by causing normally-functioning proteins to turn into diseased copies. </p>
<p>This, and the fact tau proteins are present across a range of conditions, makes it hard to determine the tau strains specific to Alzheimer’s disease.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171070/original/file-20170525-23245-1nbxqkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171070/original/file-20170525-23245-1nbxqkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171070/original/file-20170525-23245-1nbxqkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171070/original/file-20170525-23245-1nbxqkg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171070/original/file-20170525-23245-1nbxqkg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171070/original/file-20170525-23245-1nbxqkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171070/original/file-20170525-23245-1nbxqkg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171070/original/file-20170525-23245-1nbxqkg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The accumulation of amyloid protein in the brain is found in Alzheimer’s disease.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>We are <a href="http://www.alzforum.org/news/conference-coverage/next-generation-tau-pet-tracers-strut-their-stuff">still in the early stages</a> of studying tau in the brain. So far, <a href="https://www.newscientist.com/article/2082820-toxic-form-of-tau-protein-foils-memory-formation-in-alzheimers/">findings suggest</a> increased tau in memory-related areas of the brain is closely related to memory decline, even in healthy older adults.</p>
<p>But how amyloid plaques and tau tangles interact to influence the onset of Alzheimer’s disease remains a puzzle for researchers. Amyloid first begins to <a href="http://www.nationalacademies.org/hmd/%7E/media/353F303C759D406C8B893618DF9260F7.ashx">appear in the outer edges of the brain</a> (what we call the “cortex”), which is where higher-order cognitive functions are located. </p>
<p>Tau <a href="https://news.usc.edu/91957/researchers-pinpoint-brain-region-as-ground-zero-of-alzheimers-disease/">first appears deep in the brain</a>, very early in the areas of the brain stem related to sleep, arousal and vigilance, and subsequently in <a href="http://www.massgeneral.org/News/pressrelease.aspx?id=1861">memory centres</a> like the entorhinal cortex and hippocampus. </p>
<p>Interestingly, while high levels of amyloid plaques can be seen in healthy older adults, the plaques do not seem to affect cognitive function to the same degree as tau tangles. This has led some researchers to suggest that <a href="http://www.sciencemag.org/news/2016/05/tau-protein-not-amyloid-may-be-key-driver-alzheimer-s-symptoms">amyloid is necessary, but not sufficient by itself,</a> to result in dementia symptoms.</p>
<p>Another big question is which comes first, amyloid or tau? <a href="https://www.ncbi.nlm.nih.gov/pubmed/22002422">A seminal autopsy study</a> of 2,332 brains aged between ten and 90 years old showed tau appears as early as in people’s 20s and will keep accumulating across the lifespan, even in healthy people, until death. </p>
<p>One working hypothesis is that once amyloid appears on the scene, <a href="http://www.alzforum.org/news/research-news/brain-imaging-suggests-av-unleashes-deadly-side-tau">tau will accelerate its misfolding</a>, which will <a href="http://www.alzforum.org/news/conference-coverage/tau-pet-studies-agree-tangles-follow-amyloid-precede-atrophy">promote more amyloid and brain cell death</a>. A <a href="http://www.alzforum.org/news/conference-coverage/amyloid-and-neurodegeneration-have-different-underlying-genetics">commonly used analogy</a> is that tau represents the “gun” and amyloid the “bullet”.</p>
<h2>The role of genes</h2>
<p>So how does amyloid appear on the scene in the first place? <a href="http://www.mayoclinic.org/diseases-conditions/alzheimers-disease/in-depth/alzheimers-genes/art-20046552">Genes</a> may play an important role. </p>
<p>If you inherit the Alzheimer’s disease gene from only one parent and still get the disease, it is known as <a href="http://www.dian-info.org/">dominantly inherited Alzheimer’s disease</a>, or familial or autosomal dominant Alzheimer’s disease. Here, <a href="http://www.alzforum.org/early-onset-familial-ad/overview/what-early-onset-familial-alzheimer-disease-efad">mutations in one of three genes</a> (amyloid precursor protein, presenilin 1 or presenilin 2) cause a rapid accumulation of amyloid in the brain. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/171072/original/file-20170525-23232-1odlb05.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171072/original/file-20170525-23232-1odlb05.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/171072/original/file-20170525-23232-1odlb05.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=561&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171072/original/file-20170525-23232-1odlb05.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=561&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171072/original/file-20170525-23232-1odlb05.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=561&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171072/original/file-20170525-23232-1odlb05.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=705&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171072/original/file-20170525-23232-1odlb05.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=705&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171072/original/file-20170525-23232-1odlb05.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=705&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Familial Alzheimer’s disease results in severe loss of brain volume and memory at a devastatingly young age.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>This results in severe loss of brain volume and memory at a devastatingly young age (approximately 40 years old). Dominantly inherited Alzheimer’s disease is rare in the <a href="http://www.dian-info.org/institutions_Australia.htm">Australian population</a>, accounting for only 1% of all Alzheimer’s disease cases. </p>
<p>However, people who carry these mutations have a 99.9% chance of developing the disease, and a 50% chance of passing the mutations to their children.</p>
<p>Amyloid also accumulates with age. <a href="http://www.alz.org/alzheimers_disease_causes_risk_factors.asp">Age is the greatest risk factor</a> for sporadic Alzheimer’s disease (which accounts for 99% of Alzheimer’s disease cases). As the average age of onset for sporadic Alzheimer’s disease is 80, it is sometimes called late-onset Alzheimer’s disease. </p>
<p>The strongest genetic risk factor for sporadic Alzheimer’s disease is a gene called “<a href="https://www.nia.nih.gov/alzheimers/publication/alzheimers-disease-genetics-fact-sheet">apolipoprotein E (APOE) ε4</a>”, and emerging research suggests this increased risk may be due to inefficiencies in clearing amyloid from the brain. The ε4 gene is not itself predictive or diagnostic of Alzheimer’s disease. Only 40% of patients carry the ε4 gene, and many carriers do not develop the disease. </p>
<h2>Diet, diabetes and obesity</h2>
<p>Diet has long been seen as a <a href="https://www.thl.fi/fi/web/thlfi-en/research-and-expertwork/projects-and-programmes/finger-research-project">potential preventive factor</a> against dementia risk. However, the effects of dietary supplements (such as omega-III fatty acids) and adherence to specific diets (such as the <a href="http://www.alz.org/brain-health/adopt_healthy_diet.asp">Mediterranean diet</a>) <a href="http://www.cochrane.org/CD009002/DEMENTIA_omega-3-fatty-acids-treatment-dementia">have not been entirely convincing</a>. Evidence is yet to definitively show any particular diet or supplement has a substantial effect on reducing dementia risk or even memory decline.</p>
<p>Some evidence <a href="http://www.mayoclinic.org/diseases-conditions/alzheimers-disease/in-depth/diabetes-and-alzheimers/art-20046987">links type 2 diabetes</a> with risk of Alzheimer’s disease. But there is stronger support for an association between <a href="http://www.thelancet.com/journals/landia/article/PIIS2213-8587(15)00033-9/abstract">weight</a> (body mass index, or BMI) and dementia. </p>
<p>Higher BMI (over 40) is linked with greater risk of premature death and increased risk of dementia compared with people of normal weight. Evidence also suggests people with lower BMI (under 18) in midlife and beyond have a significantly increased risk of dementia compared to those in healthy ranges (18.5 to 25). </p>
<p>A recent paper suggests <a href="http://www.alzforum.org/news/research-news/no-being-thin-does-not-lead-alzheimers-disease">low BMI does not cause Alzheimer’s disease</a> but that lower BMI may arise as a result of brain changes, such as appetite suppression, that occur early due to the disease.</p>
<p>Some studies have also suggested Alzheimer’s disease can be known as <a href="http://www.newyorker.com/magazine/2017/04/03/is-fat-killing-you-or-is-sugar">“type 3” diabetes</a>, as patients show poorer energy consumption in the brain. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769828/">Some researchers suggest this is driven by insulin resistance</a>. However, this a controversial area of research and study results to this effect need independent replication.</p>
<h2>Physical activity</h2>
<p>Studies now suggest exercise <a href="http://www.health.harvard.edu/mind-and-mood/can-you-grow-new-brain-cells">can increase neuroplasticity</a> in the brain. Neuroplasticity refers to the brain’s ability to form new connections between nerve networks, particularly in memory centres.</p>
<p>Breaking a sweat may <a href="http://www.sciencemag.org/news/2013/10/how-exercise-beefs-brain">increase levels of a protein</a> called the brain-derived neurotrophic factor, which induces the growth and survival of brain cells. Just as protein shakes may help muscles grow after exercise, this protein may <a href="http://www.huffingtonpost.com/paul-spector-md/your-brain-the-new-users-_b_9608948.html">strengthen the brain’s ability</a> to cope with injury or disease, not just Alzheimer’s. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171074/original/file-20170526-23230-6dwe6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171074/original/file-20170526-23230-6dwe6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171074/original/file-20170526-23230-6dwe6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171074/original/file-20170526-23230-6dwe6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171074/original/file-20170526-23230-6dwe6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171074/original/file-20170526-23230-6dwe6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171074/original/file-20170526-23230-6dwe6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171074/original/file-20170526-23230-6dwe6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Exercise can help the brain repair nerve connections.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<h2>Sleep</h2>
<p>Sleep <a href="http://www.npr.org/sections/health-shots/2016/01/04/460620606/lack-of-deep-sleep-may-set-the-stage-for-alzheimers">problems are common</a> in patients with Alzheimer’s disease. It is likely brain regions that regulate sleep-wake cycles deteriorate, resulting in sleep disruptions. </p>
<p><a href="http://www.alzforum.org/news/research-news/sleep-and-brain-cleansing-fresh-insights-regulation-and-disruption">Animal studies</a> suggest disrupted sleep may result in increased amyloid accumulation. This is because a waste-draining system (known as the glymphatic system proposed to be involved in clearing amyloid from the brain) is <a href="http://www.cell.com/neuron/abstract/S0896-6273(17)30088-0">significantly more active</a> when people are asleep, and less effective during sleep disruption. </p>
<p>While research into the mechanisms behind sleep and amyloid clearance is still in the early stages, mounting evidence supports the idea sleep disturbances, or <a href="https://www.bumc.bu.edu/busm/2017/02/23/prolonged-sleep-may-predict-dementia-risk/">abnormal sleeping patterns</a>, may be an early <a href="https://www.researchgate.net/profile/Bryce_Mander/publication/304191436_Sleep_A_Novel_Mechanistic_Pathway_Biomarker_and_Treatment_Target_in_the_Pathology_of_Alzheimer's_Disease/links/5775841b08ae4645d60bad5e.pdf">indicator of Alzheimer’s disease</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/171075/original/file-20170526-23230-id3l9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171075/original/file-20170526-23230-id3l9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/171075/original/file-20170526-23230-id3l9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=882&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171075/original/file-20170526-23230-id3l9a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=882&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171075/original/file-20170526-23230-id3l9a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=882&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171075/original/file-20170526-23230-id3l9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1109&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171075/original/file-20170526-23230-id3l9a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1109&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171075/original/file-20170526-23230-id3l9a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1109&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sleep disturbance may be an early indicator of Alzheimer’s disease.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<h2>Mood</h2>
<p>Earlier-life depression has been associated with <a href="https://newoldage.blogs.nytimes.com/2013/05/01/does-depression-contribute-to-dementia/?_r=0">a doubled risk of developing dementia</a>. Recent <a href="http://www.neurology.org/content/88/4/371.short">evidence also suggests</a> anxiety, stress and elevated cortisol (stress-hormone) levels may play a role. </p>
<p>While the mechanisms explaining how mood might increase dementia risk remain unclear, <a href="http://www.nature.com/nrneurol/journal/v7/n6/abs/nrneurol.2011.60.html">studies suggest</a> symptoms of anxiety or depression may be associated with factors that increase your risk of vascular conditions such as heart disease and stroke. </p>
<p>They have also been associated with increasing levels of amyloid in the brain, and increased inflammation.</p>
<h2>Cognitive reserve or resilience</h2>
<p>Some people with high amyloid in their brains do not develop Alzheimer’s disease. It is suggested these people have “cognitive reserve”, which makes them able to <a href="https://academic.oup.com/brain/article/137/4/1167/371918/Compensatory-mechanisms-in-higher-educated">better compensate</a> for, or be more resilient to, increasing levels of disease in the brain. </p>
<p>This term “cognitive reserve” refers to any psychological and social factors (such as <a href="http://www.alzforum.org/news/research-news/cognitive-reserve-more-evidence-it-prevents-neurodegeneration">higher levels of education, occupational attainment or intelligence</a>) that could increase one’s chances of compensating for disease burden.</p>
<p>However, other research suggests individuals with cognitive reserve are also more likely to exhibit a <a href="http://www.neurology.org/content/75/11/990.short">sudden and precipitous drop</a> in memory performance at a later stage, unlike the “slow and steady” decline that is characteristic of most Alzheimer’s disease cases. As such, while cognitive reserve may be protective to a degree, it may simply delay disease onset.</p>
<h2>Preventing Alzheimer’s disease</h2>
<p>While a <a href="http://www.sciencemag.org/news/2017/02/another-alzheimers-drug-flops-pivotal-clinical-trial">cure continues to elude us</a>, many Alzheimer’s experts now realise <a href="http://news.harvard.edu/gazette/story/2017/04/harvard-researchers-plot-early-attack-against-alzheimers/">early diagnosis and intervention</a> is key to stopping the disease in its tracks. </p>
<p>If brain shrinkage has already begun, removing amyloid from the brain is unlikely to be effective. Recent <a href="http://www.sciencemag.org/news/2016/03/why-big-change-lilly-s-alzheimer-s-trial-not-evidence-its-drug-has-failed-again">clinical trials</a>, in which amyloid plaques were removed from the brains of Alzheimer’s disease patients, showed cognitive performance and clinical symptoms did not drastically improve over the course of the trial. </p>
<p>Clinical trials experts are <a href="http://www.tedmed.com/speakers/show?id=6607">turning their gaze</a> to earlier stages in the disease trajectory. For instance, <a href="https://www.florey.edu.au/alzheimers-disease">Australian researchers are recruiting participants</a> for a study that will test drugs that aim to remove amyloid in healthy older adults with high levels of amyloid plaques.</p>
<p>Additionally, we and other scientists are trying to understand factors that contribute to amyloid accumulation, so it can be stopped before it even starts. </p>
<p>This involves studying middle-aged adults, and following them over a long time to determine what combinations of genetic and environmental factors put people at risk of Alzheimer’s disease, or protect them against it. If you’d like to be a part of such a study in middle-aged Australians, you can head to the <a href="https://www.healthybrainproject.org.au/">Healthy Brain Project</a>.</p>
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<a href="https://images.theconversation.com/files/171076/original/file-20170526-23260-6jor39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171076/original/file-20170526-23260-6jor39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171076/original/file-20170526-23260-6jor39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171076/original/file-20170526-23260-6jor39.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171076/original/file-20170526-23260-6jor39.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171076/original/file-20170526-23260-6jor39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171076/original/file-20170526-23260-6jor39.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171076/original/file-20170526-23260-6jor39.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Engaging your brain can be helpful in reducing dementia risk.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
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<p>While the brain-training sector is worth millions of dollars annually, there is <a href="https://www.theatlantic.com/science/archive/2016/10/the-weak-evidence-behind-brain-training-games/502559/">no convincing evidence</a> that brain training (computerised programs aimed at improving your memory through games and puzzles) can <a href="https://www.scientificamerican.com/article/brain-training-doesn-t-make-you-smarter/">result in better cognitive abilities</a> in everyday life. </p>
<p>But maintaining physical, social and brain health is an <a href="https://www.theguardian.com/society/2015/mar/12/dancing-sudoku-fish-and-fruit-the-keys-to-a-mentally-alert-old-age">important component of reducing dementia risk</a>, which all Australians can implement in their daily lives. Learning a new language, picking up bridge, travelling and going back to study are ideal examples as they incorporate brain challenges and increase social engagement, which are both important for dynamically engaging the brain.</p><img src="https://counter.theconversation.com/content/75847/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yen Ying Lim receives funding from the National Health and Medical Research Council, the Australian Research Council, and the Alzheimer's Association. </span></em></p><p class="fine-print"><em><span>Rachel Buckley receives funding from the National Health and Medical Research Council, the Australian Research Council and the Brain Foundation. </span></em></p>Alzheimer’s disease is the most common form of dementia, but treatments are still far from successful in clinical trials. Here is what we know about the disease, and what is yet to be uncovered.Yen Ying Lim, Research Fellow, Florey Institute of Neuroscience and Mental HealthRachel Buckley, Research Fellow, Harvard Medical School, Research Fellow, Florey Institute of Neuroscience and Mental HealthLicensed as Creative Commons – attribution, no derivatives.