tag:theconversation.com,2011:/us/topics/nerve-signal-39559/articlesNerve signal – The Conversation2021-09-13T12:14:14Ztag:theconversation.com,2011:article/1646552021-09-13T12:14:14Z2021-09-13T12:14:14ZWhat happens when your foot falls asleep?<figure><img src="https://images.theconversation.com/files/417576/original/file-20210824-17-1ma6ikr.jpg?ixlib=rb-1.1.0&rect=494%2C1005%2C4994%2C2982&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">That pins-and-needles feeling can come from sitting in the same position for a while.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/legs-of-a-girl-wearing-dotted-socks-royalty-free-image/1195442823">Westend61 via Getty Images</a></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><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<blockquote>
<p><strong>What happens when your foot falls asleep? – Helen E., age 8, Somerville, Massachusetts</strong></p>
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<p>Imagine you’ve just sat down to watch your favorite TV show. You decide to snuggle in with your legs crisscrossed because you find it more comfortable that way.</p>
<p>When the episode ends, you try to stand up and suddenly your right foot isn’t working. At first you just can’t move it, then it feels like it has pins and needles all over it. For a minute or two it feels uncomfortable and weird, but soon enough you are able to stand up and walk around normally.</p>
<p>What just happened?</p>
<p><a href="https://scholar.google.com/citations?user=gn8ZiLMAAAAJ&hl=en&oi=ao">I’m an exercise physiologist</a> – a scientist who studies what happens to our bodies when we move and exercise. The goal of much of my research has been to understand how the brain talks to and controls the different parts of our bodies. When your foot falls asleep, there is something wrong with the communication between your brain and the muscles in that area.</p>
<p>Every time you decide to move your body, whether it’s standing up, walking around or playing sports, your brain sends signals to your muscles to make sure they move correctly. When the brain is unable to talk with a muscle or groups of muscles, some weird things can happen – including that part of your body getting that weird falling-asleep sensation.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/L6w0_j6mWbo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An animation explains how the nervous system works.</span></figcaption>
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<p>It usually starts with a sense of numbness or tingling in that area. This sensation, which people often also call “pins and needles,” is technically known as <a href="https://www.racgp.org.au/afp/2015/march/paraesthesia-and-peripheral-neuropathy/">paresthesia</a>.</p>
<p>Some people mistakenly think a lack of blood flow causes this feeling. They imagine the “asleep” feeling happens when your blood, which carries nutrients all over your body, is unable to get to your foot. But that’s not right.</p>
<p>When your foot falls asleep, it’s actually because the <a href="https://doi.org/10.2165/00007256-200232060-00003">nerves that connect the brain to the foot</a> are getting squished thanks to the position you’re sitting in. Remember, it’s these nerves that carry messages back and forth to let your brain and your foot communicate with each other. If the nerves have been compressed for a little while, you won’t have much feeling in your foot because it can’t get its normal messages through to your brain about how it feels or if it’s moving.</p>
<p>Once you start to move around again, the pressure on the nerves is released. They “wake up” and you’ll start to notice a “pins and needles” feeling. Don’t worry, that feeling will only last for a few minutes and then everything will feel normal again.</p>
<p>Now comes the important question: Is this dangerous? Most of the time, when your foot, or any other body part, falls asleep, it is temporary and nothing to worry about. In fact, since it lasts for only a minute or two, you may not even remember it happened by the end of the day.</p>
<p>Even though it’s not causing any permanent damage, you might still want to avoid the uncomfortable feeling that comes when your foot falls asleep. Here are a couple of tips that may help:</p>
<ul>
<li>Switch your position often.</li>
<li>Don’t cross your legs for very long.</li>
<li>When you are sitting for a long time, try standing up every so often.</li>
</ul>
<p>You probably can’t 100% prevent your foot from ever falling asleep. So don’t worry when it happens every once in a while. It’ll go away pretty quickly – and maybe it can remind you of all the important brain messages your nerves are usually transmitting without your even noticing.</p>
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<p class="fine-print"><em><span>Zachary Gillen does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An exercise physiologist explains how it’s a problem of communication between your brain and your body.Zachary Gillen, Assistant Professor of Exercise Physiology, Mississippi State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1306372020-07-16T12:12:05Z2020-07-16T12:12:05ZHow brains do what they do is more complex than what anatomy on its own suggests<figure><img src="https://images.theconversation.com/files/347388/original/file-20200714-139854-1ma5ygr.jpg?ixlib=rb-1.1.0&rect=289%2C52%2C3470%2C2388&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists are still piecing together the puzzle of how the brain works.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/network-data-forming-ai-robot-face-and-brain-royalty-free-image/1189020672">Yuichiro Chino/Moment via Getty Images</a></span></figcaption></figure><p>How the brain works remains a puzzle with only a few pieces in place. Of these, one big piece is actually a conjecture: that there’s a relationship between the <a href="https://doi.org/10.3390/bs8040039">physical structure of the brain and its functionality</a>. </p>
<p>The brain’s jobs include interpreting touch, visual and sound inputs, as well as speech, reasoning, emotions, learning, fine control of movement and many others. Neuroscientists presume that it’s the brain’s anatomy – with its hundreds of billions of nerve fibers – that make all of these functions possible. The brain’s “living wires” are connected in elaborate neurological networks that give rise to human beings’ amazing abilities.</p>
<p>It would seem that if scientists can map the nerve fibers and their connections and record the timing of the impulses that flow through them for a higher function such as vision, they should be able to solve the question of how one sees, for instance. Researchers are getting better at mapping the brain using <a href="https://www.sciencedirect.com/topics/neuroscience/tractography">tractography</a> – a technique that visually represents nerve fiber routes using 3D modeling. And they’re getting better at recording how information moves through the brain by using enhanced functional magnetic resonance imaging to measure blood flow.</p>
<p>But in spite of these tools, no one seems much closer to figuring out <a href="https://www.youtube.com/watch?v=lRmdLgknI28">how we really see</a>. Neuroscience has only a rudimentary understanding of how it all fits together.</p>
<p>To address this shortcoming, <a href="https://scholar.google.com/citations?user=7z-nA_kAAAAJ&hl=en&oi=ao">my team’s bioengineering research</a> focuses on relationships between brain structure and function. The overall goal is to scientifically explain all the connections – both anatomical and wireless – that activate different brain regions during cognitive tasks. We’re working on complex models that better capture what scientists know of brain function.</p>
<p>Ultimately a clearer picture of structure and function may fine-tune the ways brain surgery attempts to correct structure and, conversely, medication tries to correct function.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/347390/original/file-20200714-18-rnnul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/347390/original/file-20200714-18-rnnul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/347390/original/file-20200714-18-rnnul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/347390/original/file-20200714-18-rnnul0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/347390/original/file-20200714-18-rnnul0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/347390/original/file-20200714-18-rnnul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/347390/original/file-20200714-18-rnnul0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/347390/original/file-20200714-18-rnnul0.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">Electric near-field connections provide another level of communication within the brain.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/brain-storm-royalty-free-image/686932281">PM Images/Stone via Getty Images</a></span>
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<h2>Wireless hot spots in your head</h2>
<p>Cognitive functions such as reasoning and learning use a number of distinct brain regions in a time-sequenced manner. Anatomy alone – the neurons and nerve fibers – cannot explain the excitation of these regions, concurrently or in tandem. </p>
<p>Some connections are actually “wireless.” These are <a href="https://www.intechopen.com/books/electric-field/the-primary-role-of-the-electric-near-field-in-brain-function">electric near-field connections</a>, and not the physical connections captured in tractographs.</p>
<p>[<em><a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=experts">Expertise in your inbox. Sign up for The Conversation’s newsletter and get expert takes on today’s news, every day.</a></em>]</p>
<p>My research team has worked for several years detailing the <a href="https://doi.org/10.1109/TCBB.2019.2941689">origins of these wireless connections</a> and measuring their field strengths. A very simple analogy of what is going on in the brain is how a wireless router works. The internet is delivered to a router via a wired connection. The router then sends the information to your laptop using wireless connections. The overall system of information transfer works because of both wired and wireless connections. </p>
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<a href="https://images.theconversation.com/files/347391/original/file-20200714-139969-idshml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/347391/original/file-20200714-139969-idshml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/347391/original/file-20200714-139969-idshml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=508&fit=crop&dpr=1 600w, https://images.theconversation.com/files/347391/original/file-20200714-139969-idshml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=508&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/347391/original/file-20200714-139969-idshml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=508&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/347391/original/file-20200714-139969-idshml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=639&fit=crop&dpr=1 754w, https://images.theconversation.com/files/347391/original/file-20200714-139969-idshml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=639&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/347391/original/file-20200714-139969-idshml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=639&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Electric fields stem from charged particles flowing in and out of neurons at their uninsulated nodes of Ranvier.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/neuron-anatomy-structure-of-a-nerve-cell-royalty-free-illustration/1161436382">ttsz/iStock via Getty Images Plus</a></span>
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<p>In the case of the brain, nerve cells conduct electrical impulses down long threadlike arms called axons from the cell body to other neurons. Along the way, wireless signals are naturally emitted from uninsulated portions of nerve cells. These spots that lack the protective insulation that wraps the rest of the axon are called <a href="https://www.ncbi.nlm.nih.gov/books/NBK537273/">nodes of Ranvier</a>.</p>
<p>The nodes of Ranvier allow charged ions to diffuse in and out of the neuron, propagating the electrical signal down the axon. As the ions flow in and out, electric fields are generated. The intensity and structure of these fields depends on the activity of the nerve cell. </p>
<p>Here at the <a href="https://www.globalneuronetworks.com/">Global Center for Neurological Networks</a> we’re focusing on how these <a href="https://theconversation.com/listening-in-to-brain-communications-without-surgery-111038">wireless signals work in the brain</a> to communicate information. </p>
<h2>The brain’s nonlinear world</h2>
<p>Investigations into how excited brain regions match up with cognitive functions make another mistake when they rely on assumptions that lead to overly simple models.</p>
<p>Researchers tend to model the relationship as <a href="https://doi.org/10.1101/074856">linear with a single variable</a>, measuring the average size of a single brain region’s response. It’s the logic behind the <a href="https://www.explainthatstuff.com/hearingaids.html">design of the first hearing aid</a> – if a person’s voice grows twice as loud, the ear should respond twice as much.</p>
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<figcaption>
<span class="caption">Hearing aid users know that just doubling the sensory input is a rudimentary fix.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-wearing-hearing-aid-in-ear-royalty-free-image/618545470">AndreyPopov/iStock via Getty Images Plus</a></span>
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<p>But hearing aids have greatly improved over the years as researchers have come to better understand that the ear is not a linear system, and a form of nonlinear compression is needed to match the sounds generated to the listener’s capability. In fact, most <a href="https://www.nature.com/articles/s41598-017-02665-5">living things do not have sensing systems that respond in a linear, one-to-one manner to stimuli</a>.</p>
<p>Linear models assume that if the input to a system is doubled, the output of that system will also be doubled. This is not true of nonlinear models, where many output values can exist for single value of the input. And most scientists agree that <a href="https://doi.org/10.1007/s12043-018-1559-4">neural computations are in fact nonlinear</a>.</p>
<p>A crucial question in understanding the link between brain and behavior is how the brain decides the best course of action among competing alternatives. For example, the frontal cortex of the brain makes optimal choices by <a href="https://doi.org/10.1162/jocn.2009.21100">computing many quantities, or variables</a> – calculating the potential payoff, the probability of success and the cost in terms of time and effort. Since the system is nonlinear, doubling the potential payoff may make a final decision much more than twice as likely.</p>
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<iframe src="https://player.vimeo.com/video/394259925" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">The flow of information through the brain is much more complex and dynamic than a 2D model can adequately represent.</span></figcaption>
</figure>
<p>Linear models miss out on the rich variety of possibilities that can occur in brain function, especially those beyond what anatomical structure would suggest. It’s like the difference between a 2D and 3D representation of the world around us.</p>
<p>Current linear models just describe the average level of excitation in a brain region, or the flow across a brain surface. That’s much less information than my colleagues and I use when building our nonlinear models from both enhanced functional magnetic resonance imaging and electric near-field bioimaging data. Our models provide a 3D image of information flow across the surfaces of the brain and to depths within it – and get us closer to representing how it all works.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/347397/original/file-20200714-18-1u8ov21.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/347397/original/file-20200714-18-1u8ov21.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/347397/original/file-20200714-18-1u8ov21.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/347397/original/file-20200714-18-1u8ov21.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/347397/original/file-20200714-18-1u8ov21.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/347397/original/file-20200714-18-1u8ov21.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/347397/original/file-20200714-18-1u8ov21.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/347397/original/file-20200714-18-1u8ov21.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">A healthy-looking brain can have functional problems.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/angiogram-examination-royalty-free-image/1178748283">Science Photo Library via Getty Images</a></span>
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<h2>Normal anatomy, physiological dysfunction</h2>
<p>My research team is intrigued by the fact that people with totally normal-looking brain structures can still have major functional problems.</p>
<p>As part of our research into neurological dysfunction, we visit individuals in hospice, bereavement support groups, rehabilitation care facilities, trauma centers and acute care hospitals. We are consistently startled to realize that people who have lost loved ones can <a href="https://humanparts.medium.com/brain-fog-after-a-death-f6b6882c8614">exhibit similar symptoms</a> to those of patients diagnosed with Alzheimer’s disease. </p>
<p>Grief is a series of emotional, cognitive, functional and behavioral responses to death or other kinds of loss. It’s not a state, but rather a process which can either be temporary or ongoing.</p>
<p>The healthy-looking brains of those suffering <a href="https://www.psychologytoday.com/us/blog/the-truisms-wellness/201702/the-ways-we-grieve">physiological grief</a> do not have the same anatomical problems – including shrunken brain regions and disrupted connections between networks of neurons – that are found in those of people with Alzheimer’s disease.</p>
<p>We believe this is just one example of how the brain’s hot spots – those connections that are not physical – plus the richness of the brain’s nonlinear operation can lead to outcomes that wouldn’t be predicted by a brain scan. There are likely many more examples.</p>
<p>These ideas may point the way to the mitigation of serious neurological conditions through noninvasive means. <a href="https://doi.org/10.1007/s11920-013-0406-z">Bereavement therapy and noninvasive, electric near-field neuromodulation devices</a> can reduce the symptoms associated with the loss of a loved one. Perhaps these protocols and procedures should be more widely offered to patients suffering from neurological dysfunction where imaging does reveal anatomical changes. It could save some of these individuals from invasive surgical procedures.</p>
<p>Diagramming all the brain’s nonphysical links using our recent advances in electric near-field mapping, and employing what we believe are biologically realistic many-variable nonlinear models, will get us one step closer to where we want to go. Better understanding of the brain will not only reduce the need for invasive operating procedures to correct function, but will also lead to better models for what the brain does best: computation, memory, networking and information distribution.</p><img src="https://counter.theconversation.com/content/130637/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Salvatore Domenic Morgera has received funding for research in networks from the Natural Sciences and Engineering Research Council of Canada, The Fonds de recherche du Québec - Nature et technologies, National Research Council, Communications Research Center, National Science Foundation, United States Special Operations Command, IBM, Harris Corporation, CMC Electronics, Motorola, Bell Canada, the University of South Floridak and other public and private agencies. He has founded the Global Center for Neurological Networks (globalneuronetworks.com) to create a national and international focus or research groups demonstrating a passion to understand the human brain.
</span></em></p>A bioengineer explains how a clearer picture of brain structure and function may fine-tune the ways brain surgery attempts to correct structure and medication tries to correct function.Salvatore Domenic Morgera, Professor of Electrical Engineering and Bioengineering, Tau Beta Pi Eminent Engineer, University of South FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1237512019-09-19T20:53:49Z2019-09-19T20:53:49ZYour brain has ‘landmarks’ that drive neural traffic and help you make hard decisions<figure><img src="https://images.theconversation.com/files/293136/original/file-20190919-53524-faquip.jpg?ixlib=rb-1.1.0&rect=17%2C17%2C5973%2C3970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The human brain has an estimated 100 billion neurons and 100 trillion neural connections. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1018045489?src=NGRrcFntJ0l7FG3qne4tfA-1-12&size=huge_jpg">shutterstock</a></span></figcaption></figure><p>Brain regions exchange information by sending and receiving signals through a network of nerve connections. </p>
<p>This exchange is crucial to all aspects of the brain’s functioning, including how we experience the world, form and retrieve memories, and make decisions. </p>
<p>But scientists don’t have a clear idea of how signals find their way through the brain’s complicated wiring.</p>
<p>To understand this problem, our research team spent the past three years studying <a href="https://www.pnas.org/content/115/24/6297">how brain regions communicate with each other</a>, and what we found can help us better understand how our brains function.</p>
<p>Using non-invasive MRI scans, we reconstructed the <a href="https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.0010042">network of nerve fibre bundles</a> of the human brain. This gave us a model of brain wiring, which we used to investigate how signals may travel between the brain’s regions.</p>
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<a href="https://images.theconversation.com/files/292985/original/file-20190918-187974-nqlukf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/292985/original/file-20190918-187974-nqlukf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292985/original/file-20190918-187974-nqlukf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=228&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292985/original/file-20190918-187974-nqlukf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=228&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292985/original/file-20190918-187974-nqlukf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=228&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292985/original/file-20190918-187974-nqlukf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=287&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292985/original/file-20190918-187974-nqlukf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=287&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292985/original/file-20190918-187974-nqlukf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=287&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">There are three steps in the modelling of the brain’s network of nerve fibre bundles. First, we consider the human brain’s anatomy. Then we use MRI scans to create a 3D model of all nerve connection bundles. Lastly, we reconstruct the brain’s wiring network and use it to understand communication between brain regions.</span>
<span class="attribution"><span class="source">Left: Wikimedia Commons. Centre and right: author provided.</span></span>
</figcaption>
</figure>
<p>In our research, published in <a href="https://www.nature.com/articles/s41467-019-12201-w">Nature Communications</a>, we discovered that based on how our brains are wired, certain regions are better at sending electrical signals, while others are better at receiving them. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/like-sightseeing-in-paris-a-new-model-for-brain-communication-96983">Like sightseeing in Paris – a new model for brain communication</a>
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<p>This is an important discovery because it helps us understand how neural traffic is directed in the brain.</p>
<p>Malfunctions in brain communication may be the cause of many debilitating mental health conditions such as depression and schizophrenia. By understanding how brain regions communicate with each other, we can potentially develop new treatments for such diseases.</p>
<h2>Two-way connections</h2>
<p>In the brain, a nerve bundle connects two regions and allows signals to travel between them. </p>
<p>These connections can be one-way, where signals only travel in a single direction, or two-way, which allows communication both ways.</p>
<p>Scientists discovered this a long time ago by dissecting the preserved brains of humans and other animals.</p>
<p>Non-invasive MRI scans can tell us which brain regions have nerve bundles connecting them, but we can’t know whether they are one or two-way connections. </p>
<p>Also, if they’re one-way connections, we don’t know the direction of movement. This is a limitation of current brain scan technology. </p>
<p>Because scientists cannot tell the difference between a one or two-way connection in the brain, they usually assume all nerve bundles are two-way connections. This is a reasonable simplification in many cases, and <a href="https://www.nature.com/articles/nrn3901">has helped us understand a lot about the brain</a>.</p>
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Read more:
<a href="https://theconversation.com/the-brain-and-the-gut-talk-to-each-other-how-fixing-one-could-help-the-other-78841">The brain and the gut talk to each other: how fixing one could help the other</a>
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<p>But this simplification makes it difficult to study the direction in which electrical signals are travelling. While we can study communication between two parts of the brain, it’s hard to know which region is sending signals and which is receiving them. </p>
<p>Our research helped us get around this problem. </p>
<h2>Senders and receivers in the brain</h2>
<p>To better understand, imagine you’re on vacation in Paris and decide to rent a car and go for a drive. You’re driving without a destination in mind when you serendipitously arrive at the famous Arc de Triomphe.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/293118/original/file-20190919-187940-1bf4a5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/293118/original/file-20190919-187940-1bf4a5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/293118/original/file-20190919-187940-1bf4a5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293118/original/file-20190919-187940-1bf4a5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293118/original/file-20190919-187940-1bf4a5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293118/original/file-20190919-187940-1bf4a5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293118/original/file-20190919-187940-1bf4a5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293118/original/file-20190919-187940-1bf4a5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&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">‘Receivers’ in the human brain act like landmarks in cities, as they are easy to get to from other locations.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/arc-de-triomphe-paris-france-628067444?src=ulmUQQ9OaCnmudeT8Ecs9w-1-32">Shutterstock</a></span>
</figcaption>
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<p>This is not a coincidence. Cities are designed so that important places are easy to get to from many locations. While it may be easy to drive from the car rental agency to the Arc de Triomphe, starting from the famous landmark and accidentally coming back to the agency is less likely.</p>
<p>Our research shows brain communication may work in a similar way. We found that certain regions are, on average, quickly accessible from everywhere else in the brain. We call these regions “receivers”. </p>
<p>Other regions are, on average, good at efficiently reaching most places in the brain, but may not be so easy to get to. We call these regions “senders”.</p>
<p>We found that the division of the brain’s regions into senders and receivers matches previous ideas about how the brain operates.</p>
<p>Senders are in charge of sensory signals such as visual or auditory information. They are the first regions to deal with information coming from the outside world, and can efficiently send this data to the rest of the brain.</p>
<p>On the other hand, receivers are important for complicated thoughts and problem solving. They act as meeting points for information coming from many other regions. They then collect and process this data, with the goal of ensuring our decisions make sense with what is going on in the outside world.</p>
<h2>New possibilities</h2>
<p>Our research shows that knowledge about sender and receiver regions in the brain can be obtained from a two-way connection model of the human brain’s wiring. Importantly, we reconstructed the wiring using non-invasive MRI scans. </p>
<p>Until now, scientists thought that understanding how the brain’s wiring directs neural traffic was only possible by dissecting the brains of humans and other animals after their death.</p>
<p>Our research introduces possibilities to better understand brain functioning in living people, and how disruptions in neural communication may lead to mental disorders.</p><img src="https://counter.theconversation.com/content/123751/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 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>Sections in the brain called “senders” and “receivers” are responsible for directing neural traffic, and we are now a step closer to understanding how they work.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/1012312018-08-10T10:37:57Z2018-08-10T10:37:57ZFlip a switch and shut down seizures? New research suggests how to turn off out-of-control signaling in the brain<figure><img src="https://images.theconversation.com/files/231381/original/file-20180809-30449-1vejssm.jpg?ixlib=rb-1.1.0&rect=257%2C12%2C3624%2C2561&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In an epileptic brain, the neurons fire wildly.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/human-brain-impulse-mixed-media-452290207">Sergey Nivens/Shutterstock.com</a></span></figcaption></figure><p>The brain is a precision instrument. Its function depends on finely calibrated electrical activity triggering the release of chemical messages between neurons.</p>
<p>But sometimes the brain’s careful balance is knocked out of control, as in <a href="https://www.epilepsy.com/learn/about-epilepsy-basics/what-epilepsy">epilepsy</a>. Electroencephalography, or <a href="https://www.mayoclinic.org/tests-procedures/eeg/about/pac-20393875">EEG</a>, visualizes a brain’s electrical activity and can reveal how an epileptic seizure diverges from the predictable wave pattern of typical brain activity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/231337/original/file-20180809-30446-1x4fofp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/231337/original/file-20180809-30446-1x4fofp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/231337/original/file-20180809-30446-1x4fofp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=186&fit=crop&dpr=1 600w, https://images.theconversation.com/files/231337/original/file-20180809-30446-1x4fofp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=186&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/231337/original/file-20180809-30446-1x4fofp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=186&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/231337/original/file-20180809-30446-1x4fofp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=233&fit=crop&dpr=1 754w, https://images.theconversation.com/files/231337/original/file-20180809-30446-1x4fofp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=233&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/231337/original/file-20180809-30446-1x4fofp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=233&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 pattern of typical brain activity is very regular. During an epileptic seizure, the electrical activity erratically spikes.</span>
<span class="attribution"><span class="source">Rochelle Hines</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>But medicine still lacks a solution to epilepsy. There’s limited possibility of predicting a seizure, and no way to intervene even when you can predict. Although pharmaceuticals are available to people dealing with epilepsy, they are fraught with <a href="http://www.tandfonline.com/doi/full/10.1586/ern.10.71">side effects</a>, and they <a href="https://doi.org/10.3390/brainsci8040049">do not work for everyone</a>.</p>
<p>Working on a problem in <a href="https://www.hinesgroup.net">my neuroscience lab</a>, when I stop to imagine how frightening it could be to live with a brain out of control in this way, it really motivates me. Could there be a way to seize back control of these neurons gone rogue? I’ve been focusing on how a specific compartment within each brain cell <a href="https://doi.org/10.1038/s41467-018-05481-1">might be able to help us do just that</a>.</p>
<h2>An override switch for brain activity</h2>
<p>Ever since I was an undergraduate student, I’ve been fascinated with a part of the neuron called the axon initial segment. Each neuron contains this small compartment. It’s where a neuron “decides” to fire an electrical signal, sending a chemical message on to the next cell.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/231339/original/file-20180809-30467-16v50vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/231339/original/file-20180809-30467-16v50vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/231339/original/file-20180809-30467-16v50vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=925&fit=crop&dpr=1 600w, https://images.theconversation.com/files/231339/original/file-20180809-30467-16v50vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=925&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/231339/original/file-20180809-30467-16v50vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=925&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/231339/original/file-20180809-30467-16v50vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1162&fit=crop&dpr=1 754w, https://images.theconversation.com/files/231339/original/file-20180809-30467-16v50vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1162&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/231339/original/file-20180809-30467-16v50vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1162&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 axon initial segment receives signals from adjacent neurons and ‘decides’ whether its own neuron will fire an electrical signal in response.</span>
<span class="attribution"><span class="source">Rochelle Hines</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>There are specialized connections here that can exert powerful control; they can override the cell’s own “decision” about firing. This control mechanism exists to organize or pattern brain activity – a requirement for much of our behavior.</p>
<p>For example, in order to fall asleep your brain activity needs to wind down into a slow oscillation. In contrast, sharp concentration on a problem requires the pattern to pick up, producing a rapid oscillation. An <a href="https://doi.org/10.1001/jamapsychiatry.2015.0483">inability to produce and regulate these patterns</a> of brain activity has been related to numerous disorders of the brain.</p>
<p>When the axon initial segments of numerous neurons all receive a silencing signal at the same time, it results in a trough in the wave pattern of the EEG. This means that it quiets the brain’s activity, something that under normal conditions would be useful when moving between relaxed awake and sleep states.</p>
<p>If researchers could harness the power of these inhibitory connections, we could potentially reset the brain’s activity pattern whenever we want to. It could be a way to wrest back control in an epileptic brain.</p>
<h2>Molecules that mediate the message</h2>
<p>To begin understanding how to regulate this power of the axon initial segment, my colleagues and I first needed to understand the molecular partnerships at these connections. For inhibition to be effective at the axon initial segment, there needs to be the right equipment available to receive the signal. In the case of inhibition in the brain, this equipment is <a href="https://doi.org/10.1016/j.conb.2011.10.007">the GABA A receptor</a>.</p>
<p>With collaborators <a href="https://scholar.google.com/citations?hl=en&user=LP1GjaQAAAAJ&view_op=list_works&sortby=pubdate">Hans Maric</a> and <a href="http://www.rudolf-virchow-zentrum.de/en/research/research-groups/schindelin-group/research.html">Hermann Schindelin</a>, we identified a close and exclusive partnership between two proteins – the GABA A receptor α2 subunit and collybistin. Figuring out the close relationship between these two molecules answers some open questions about how proteins at inhibitory contact sites might be interacting. We knew that the GABA A receptor α2 subunit is found at the axon initial segment, but researchers didn’t understand how it gets there or is kept there. Collybistin could be key.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/231375/original/file-20180809-30470-1gzgil4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/231375/original/file-20180809-30470-1gzgil4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/231375/original/file-20180809-30470-1gzgil4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=342&fit=crop&dpr=1 600w, https://images.theconversation.com/files/231375/original/file-20180809-30470-1gzgil4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=342&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/231375/original/file-20180809-30470-1gzgil4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=342&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/231375/original/file-20180809-30470-1gzgil4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=430&fit=crop&dpr=1 754w, https://images.theconversation.com/files/231375/original/file-20180809-30470-1gzgil4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=430&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/231375/original/file-20180809-30470-1gzgil4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=430&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Together, the GABA receptor protein and collybistin work together to receive the message from the neurotransmitter GABA within this important part of the neuron.</span>
<span class="attribution"><span class="source">Rochelle Hines</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>So now we thought that these two proteins could be working together at the axon initial segment. To take it further, my postdoctoral mentor <a href="https://scholar.google.com/citations?user=8G-86gkAAAAJ&hl=en">Stephen Moss</a> and I wanted to understand what implications this might have for connections at the axon initial segment, and ultimately how the brain works. To try to figure that out, we created a genetic mutation that resulted in the two proteins being unable to connect.</p>
<p>Neurons of mice with this mutation did, in fact, lose inhibitory connections onto the axon initial segment. Inhibitory connections onto other parts of brain cells remained intact, again supporting the idea that this protein partnership is exclusive, and specifically important at the axon initial segment. </p>
<p>Mice with this mutation experience seizures during development. When they grow into adults, these mice no longer show behavioral signs of seizure. In some forms of pediatric epilepsy, kids can also “outgrow” their seizures. So this mutation is extremely valuable in providing a possible model for human pediatric epilepsy. We hope it can help us understand more clearly what happens in the brain during epilepsy, and also to design and test better therapies, like the selective compound developed by <a href="https://www.astrazeneca.com/our-science/IMED.html">AstraZeneca whose scientists</a> also contributed to this project.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/231343/original/file-20180809-30461-15y51yr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/231343/original/file-20180809-30461-15y51yr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/231343/original/file-20180809-30461-15y51yr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/231343/original/file-20180809-30461-15y51yr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/231343/original/file-20180809-30461-15y51yr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/231343/original/file-20180809-30461-15y51yr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=521&fit=crop&dpr=1 754w, https://images.theconversation.com/files/231343/original/file-20180809-30461-15y51yr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=521&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/231343/original/file-20180809-30461-15y51yr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=521&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Understanding more about these molecules could help researchers design what is essentially an ‘off switch’ for a brain that’s firing out of control.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/skeleton-xray-brain-off-male-his-115340698">Jeff Cameron Collingwood/Shutterstock.com</a></span>
</figcaption>
</figure>
<h2>A quantitative but early step</h2>
<p>Neuroscientists have long speculated about the partnership between the GABA A receptor and collybistin. Now <a href="https://doi.org/10.1038/s41467-018-05481-1">our results, recently published in Nature Communications</a>, define it quantitatively.</p>
<p>While we know GABA A receptors – which respond to the neurotransmitter GABA – control inhibitory signaling, we’re still figuring out how it all works. GABA signaling is diverse, with various connection types that exert distinct control over cell firing – something else we need to work to understand. And dysfunction in GABA signaling is <a href="https://doi.org/10.3389/fnmol.2018.00132">involved in a number of other disorders</a> of the brain, too, in addition to epilepsy. </p>
<p>The ultimate goal of this research is to design treatments that might be able to control inhibitory connections at the axon initial segment. We’d like to be in charge of that switch, able to turn off the out-of-control neural firing seen during an epileptic seizure.</p>
<p>I am imagining life with epilepsy, and I am also imagining life without it.</p><img src="https://counter.theconversation.com/content/101231/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rochelle Hines received funding from the Canadian Institute for Health Research as a postdoctoral fellow, and currently acts as a consultant for Rapid Dose Therapeutics, a relationship that is regulated by the University of Nevada Las Vegas. Her collaborator Stephen Moss serves as a consultant for AstraZeneca, a relationship that is regulated by Tufts University.</span></em></p>During epileptic seizures, neurons in the brain fire without rhyme or reason. New research identifies a possible way to wrest back control by stopping these signals before they can get started.Rochelle Hines, Assistant Professor of Psychology, University of Nevada, Las VegasLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/997312018-08-06T10:39:33Z2018-08-06T10:39:33ZBrains keep temporary molecular records before making a lasting memory<figure><img src="https://images.theconversation.com/files/230467/original/file-20180802-136652-1cvad3.jpg?ixlib=rb-1.1.0&rect=490%2C475%2C1407%2C958&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Like the day's newspaper, the brain has a temporary way to keep track of events.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/vector-silhouette-human-brain-newspaper-columns-124171039">TonTonic/Shutterstock.com</a></span></figcaption></figure><p>The first dance at my wedding lasted exactly four minutes and 52 seconds, but I’ll probably remember it for decades. Neuroscientists still don’t entirely understand this: How was my brain able to translate this less-than-five-minute experience into a lifelong memory? Part of the puzzle is that there’s a gap between experience and memory: our experiences are fleeting, but it takes hours to form a long-term memory.</p>
<p>In recent work <a href="https://doi.org/10.1016/j.neuron.2018.04.001">published in the journal Neuron</a>, <a href="https://www.niehs.nih.gov/research/atniehs/labs/ln/pi/sdp/index.cfm">my</a> <a href="https://gray.hms.harvard.edu/">colleagues</a> <a href="http://faculty.ucmerced.edu/rsaha3">and</a> <a href="https://scholar.google.com/citations?view_op=list_works&hl=en&user=9JkTJUMAAAAJ">I</a> figured out how the brain keeps temporary molecular records of transient experiences. Our finding not only helps to explain how the brain bridges the gap between experience and memory. It also allows us to read the brain’s short-term records, raising the possibility that we may one day be able to infer a person’s, or at least a laboratory mouse’s, past experience – what they saw, thought, felt – just by looking at the molecules in their brain.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/230615/original/file-20180803-41320-ye2h39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/230615/original/file-20180803-41320-ye2h39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/230615/original/file-20180803-41320-ye2h39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=423&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230615/original/file-20180803-41320-ye2h39.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=423&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230615/original/file-20180803-41320-ye2h39.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=423&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230615/original/file-20180803-41320-ye2h39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=531&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230615/original/file-20180803-41320-ye2h39.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=531&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230615/original/file-20180803-41320-ye2h39.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=531&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Electrical pulses carry signals along the branches of neurons.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Cajal_actx_inter.jpg">Santiago Ramón y Cajal</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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</figure>
<h2>Electrifying experience</h2>
<p>To uncover how the brain keeps track of an animal’s experience, we started by asking how the brain records its electrical activity. Every experience you have, from chatting with a friend to smelling french fries, corresponds to its own unique pattern of electrical activity in the nervous system and brain. These activity patterns are defined by which neurons are active and in what way they’re active.</p>
<p>For example, say you’re at the gym lifting weights. Which neurons are active is fairly straightforward: If you’re lifting with your right arm, different neurons will be active than if you’re lifting with your left arm because different neurons are connected to the muscles of each arm.</p>
<p>The way in which a neuron is active, on the other hand, encompasses an infinite number of possibilities. Neuronal activity consists of pulses of electricity that can occur in pretty much any pattern over time that you can imagine. Electrical activity can vary in duration, or whether the pulses occur in clumps or steadily. In this case, lifting a heavier weight will lead to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1514782/?page=1">more pulses per minute</a>.</p>
<p>So, it’s a combination of which neurons are active and how frequently they’re pulsing that makes your experience of lifting a 10-pound weight with your right hand different from that of lifting a 5-pound weight with your left hand.</p>
<h2>Activated neurons activate genes</h2>
<p>In our experiments, we couldn’t test every possible pattern of electrical activity, so we focused just on the way neurons record how long they are active.</p>
<p>We predicted they’d keep these records by turning on genes. All the cells in your body have pretty much the same genes encoded in their DNA. But different genes turn on depending on the type of cell and what it’s encountered in its life. Which genes are activated in a particular cell are what makes it different from other cells.</p>
<p>For about 30 years, researchers have known that neurons <a href="https://doi.org/10.1016/0896-6273(90)90106-P">turn on certain genes</a> when they’re electrically active. When a gene in a neuron is turned on, the cell sends a molecular Xerox machine to that gene’s place in the DNA. The molecular Xerox makes lots of copies of the gene in the form of new molecules. These new molecules aren’t made of DNA, but rather the closely-related RNA. These RNA molecules remain in the cell for hours to days and serve as the brain’s record of which neurons were active.</p>
<p>But we wanted to know whether the genes that are on in neurons can record not just that they’ve been at all active but also the way they’ve been active. That is, do neurons that are activated differently – for longer or shorter time periods, for instance – turn on different genes?</p>
<p>We thought they would: Long-term memories are stored in physical changes to the neurons themselves, and the type of change is determined by the pattern of electrical activity the neuron experiences. So we predicted that the brain would need to keep track not only of which neurons were active, but also the way those neurons were active in order to make those lasting changes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/230510/original/file-20180803-41351-1ovxv3.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/230510/original/file-20180803-41351-1ovxv3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/230510/original/file-20180803-41351-1ovxv3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=456&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230510/original/file-20180803-41351-1ovxv3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=456&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230510/original/file-20180803-41351-1ovxv3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=456&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230510/original/file-20180803-41351-1ovxv3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=573&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230510/original/file-20180803-41351-1ovxv3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=573&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230510/original/file-20180803-41351-1ovxv3.png?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"></a>
<figcaption>
<span class="caption">Researchers activated mouse neurons growing in a dish.</span>
<span class="attribution"><span class="source">Kelsey Tyssowski</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>In our experiments, we activated mouse neurons growing in a dish by exposing them to a chemical that turned them on. As long as the chemical was there, the neurons were active, allowing us to keep them turned on for various lengths of time.</p>
<p>We found that, indeed, neurons in a dish that are activated for different lengths of time turn on different genes. And this genetic record-keeping is unexpectedly simple: The longer neurons are active, the more genes they turn on.</p>
<p>This turned out to be true not only in neurons growing in a dish, but also in the brains of living mice. By exposing mice to bright lights, we were able to activate the neurons in the vision center of their brains for as long as the lights were on. The longer the lights shone, the more different genes turned on, their RNA copies building up in the cell. This means that the set of molecules found in a briefly active neuron is different from that found in a neuron that was active for a long time.</p>
<p>That this simple record-keeping was present in the brains of living mice suggests it’s likely also in the brains of humans.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/230502/original/file-20180803-41338-15m8wpe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/230502/original/file-20180803-41338-15m8wpe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/230502/original/file-20180803-41338-15m8wpe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230502/original/file-20180803-41338-15m8wpe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230502/original/file-20180803-41338-15m8wpe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230502/original/file-20180803-41338-15m8wpe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230502/original/file-20180803-41338-15m8wpe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230502/original/file-20180803-41338-15m8wpe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Each neuron contains a metaphorical machine that translates its electrical activity into molecular records.</span>
<span class="attribution"><span class="source">Anastasia Nizhnik and Kelsey Tyssowski</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>Temporary records of breaking news</h2>
<p>Our work only explains how neurons keep track of how long they were active, but we think neurons may well keep track of all aspects of their activity in the same way. But why would the brain keep this molecular record of an animal’s experiences?</p>
<p>I think of these molecular records as being like a newspaper. The brain writes an article about each experience by turning on a specific set of genes in a specific set of neurons. These articles – in the form of RNA molecules – will remain around for hours to days. But just as days-old newspapers are usually tossed out, the copies of the activated genes are not how the brain stories memories for decades.</p>
<p>Instead, the brain reads its temporary newspaper-like records to write its history books: long-term memories. When your brain stores a memory of an experience, it <a href="https://doi.org/10.1101/cshperspect.a021741">physically changes the connections</a> between the neurons that the experience activated. Those changes can last a lifetime – like my wedding memories. Our group thinks the genes that are on in a neuron probably tell it what kinds of changes to make, like the articles in a newspaper tell scholars what to write in history books.</p>
<h2>Reading records</h2>
<p>My colleagues and I thought that if the brain is able to read these molecular records when writing its long-term memories, we should be able to read them, too. Like any reliable record, the genes that turned on in response to short versus long activity were predictable. They were actually so predictable that we were able to figure out if a group of neurons had been activated for a long time or a short time just by looking at which genes they had turned on.</p>
<p>So far we can only read how long a neuron’s been active, but if we could fully read the brain’s records, we might be able to infer someone’s experience of their day just by looking at the RNA molecules present in their brain. We could look at the genes that are on in your neurons and figure out that in your workout this morning you lifted a 5-, not 10-, pound weight with your right, not left, hand. And we could tell that you were daydreaming about your date tonight while you did it.</p>
<p>Unfortunately for aspiring mind-readers who are willing to put aside any ethical qualms, it’s not actually possible to look at the molecules present in the brain of a living person and probably won’t be in the foreseeable future. Furthermore, we don’t entirely understand which brain activity patterns correspond to which experiences. So even if we could read these records fluently, we wouldn’t be able to infer experience.</p>
<p>Instead, we hope that understanding the brain’s record-keeping will provide an easier way to measure brain activity in lab animals for researchers trying to figure out the correspondence between experience and brain activity. Current technologies are somewhat inefficient and can only measure activity in real time, so reading the brain’s genetic records could make these experiments more feasible.</p>
<p>So while molecular mind-reading in humans stays relegated to science fiction for now, our work begins to allow scientists to read the records in the brains of lab mice. It’s a step toward understanding how the brain converts experience to electrical activity to memory.</p><img src="https://counter.theconversation.com/content/99731/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kelsey Tyssowski received funding from the National Science Foundation Graduate Research Fellowship Program. The research described here was also funded by the NIH, the Canadian Institute of Health Research, the Giovanni Armenise-Harvard Foundation, a McKnight Scholar Award, a Harvard Brain Science Initiative Bipolar Disorder Seed Grant, the Kaneb family and Kent and Liz Dauten.</span></em></p>How do brains convert experiences into memories? New research explores the chain of events by focusing on what genes shift into gear when neurons are firing.Kelsey Tyssowski, Graduate Student in Biomedical Science, Harvard 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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<strong>
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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<em>
<strong>
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>
<hr>
<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>
<hr>
<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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<p>
<em>
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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/777592017-06-14T02:23:03Z2017-06-14T02:23:03ZHelping or hacking? Engineers and ethicists must work together on brain-computer interface technology<figure><img src="https://images.theconversation.com/files/173203/original/file-20170609-4841-73vkw2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A subject plays a computer game as part of a neural security experiment at the University of Washington.</span> <span class="attribution"><span class="source">Patrick Bennett</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>In the 1995 film <a href="http://www.imdb.com/title/tt0112462/">“Batman Forever</a>,” the Riddler used 3-D television to secretly access viewers’ most personal thoughts in his hunt for Batman’s true identity. By 2011, the metrics company <a href="http://www.nielsen.com/us/en/press-room/2011/nielsen-acquires-neurofocus.html">Nielsen had acquired Neurofocus</a> and had created a “consumer neuroscience” division that uses <a href="http://www.nielsen.com/us/en/solutions/capabilities/consumer-neuroscience.html">integrated conscious and unconscious data</a> to track customer decision-making habits. What was once a nefarious scheme in a Hollywood blockbuster seems poised to become a reality.</p>
<p>Recent announcements <a href="https://www.theverge.com/2017/3/27/15077864/elon-musk-neuralink-brain-computer-interface-ai-cyborgs">by Elon Musk</a> <a href="https://techcrunch.com/2017/04/19/facebook-brain-interface/">and Facebook</a> about <a href="https://theconversation.com/melding-mind-and-machine-how-close-are-we-75589">brain-computer interface (BCI) technology</a> are just the latest headlines in an ongoing science-fiction-becomes-reality story.</p>
<p>BCIs use brain signals to control objects in the outside world. They’re a potentially world-changing innovation – imagine being paralyzed but able to “reach” for something with a prosthetic arm <a href="http://www.slate.com/blogs/future_tense/2012/12/21/jan_scheuermann_footage_of_paralyzed_woman_eating_chocolate_with_robotic.html">just by thinking about it</a>. But the revolutionary technology also raises concerns. Here at the University of Washington’s Center for Sensorimotor Neural Engineering (<a href="http://www.csne-erc.org/">CSNE</a>) we and our colleagues are researching BCI technology – and a crucial part of that includes working on issues such as neuroethics and neural security. Ethicists and engineers are working together to understand and quantify risks and develop ways to protect the public now. </p>
<h2>Picking up on P300 signals</h2>
<p>All BCI technology relies on being able to collect information from a brain that a device can then use or act on in some way. There are numerous places from which signals can be recorded, as well as infinite ways the data can be analyzed, so there are many possibilities for how a BCI can be used.</p>
<p>Some BCI researchers zero in on one particular kind of regularly occurring brain signal that alerts us to important changes in our environment. Neuroscientists call these signals “<a href="https://doi.org/10.4103/0972-6748.57865">event-related potentials</a>.” In the lab, they help us identify a reaction to a stimulus.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/172819/original/file-20170607-29557-1ggtcor.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/172819/original/file-20170607-29557-1ggtcor.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/172819/original/file-20170607-29557-1ggtcor.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=417&fit=crop&dpr=1 600w, https://images.theconversation.com/files/172819/original/file-20170607-29557-1ggtcor.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=417&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/172819/original/file-20170607-29557-1ggtcor.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=417&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/172819/original/file-20170607-29557-1ggtcor.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=524&fit=crop&dpr=1 754w, https://images.theconversation.com/files/172819/original/file-20170607-29557-1ggtcor.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=524&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/172819/original/file-20170607-29557-1ggtcor.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=524&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Examples of event-related potentials (ERPs), electrical signals produced by the brain in response to a stimulus.</span>
<span class="attribution"><span class="source">Tamara Bonaci</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In particular, we capitalize on one of these specific signals, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2715154/">called the P300</a>. It’s a positive peak of electricity that occurs toward the back of the head about 300 milliseconds after the stimulus is shown. The P300 alerts the rest of your brain to an “oddball” that stands out from the rest of what’s around you.</p>
<p>For example, you don’t stop and stare at each person’s face when you’re searching for your friend at the park. Instead, if we were recording your brain signals as you scanned the crowd, there would be a detectable P300 response when you saw someone who could be your friend. The P300 carries an unconscious message alerting you to something important that deserves attention. These signals are part of a still unknown brain pathway that aids in detection and focusing attention.</p>
<h2>Reading your mind using P300s</h2>
<p>P300s reliably occur any time you notice something rare or disjointed, like when you find the shirt you were looking for in your closet or your car in a parking lot. Researchers can use the P300 in an experimental setting to determine what is important or relevant to you. That’s led to the creation of devices like spellers that allow paralyzed individuals to type using their thoughts, <a href="https://doi.org/10.1016/0013-4694(88)90149-6">one character at a time</a>.</p>
<p>It also can be used to determine what you know, in what’s called a “<a href="https://dx.doi.org/10.3109/00207458808985770">guilty knowledge test</a>.” In the lab, subjects are asked to choose an item to “steal” or hide, and are then shown many images repeatedly of both unrelated and related items. For instance, subjects choose between a watch and a necklace, and are then shown typical items from a jewelry box; a P300 appears when the subject is presented with the image of the item he took.</p>
<p>Everyone’s P300 is unique. In order to know what they’re looking for, researchers need “training” data. These are previously obtained brain signal recordings that researchers are confident contain P300s; they’re then used to calibrate the system. Since the test measures an unconscious neural signal that you don’t even know you have, can you fool it? Maybe, if you <a href="https://doi.org/10.1111/j.1469-8986.2004.00158.x">know that you’re being probed and what the stimuli are</a>.</p>
<p>Techniques like these are still considered unreliable and unproven, and thus U.S. courts have <a href="https://doi.org/10.1176/ps.2007.58.4.460">resisted admitting P300 data as evidence</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/172821/original/file-20170607-25764-pbljrg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/172821/original/file-20170607-25764-pbljrg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/172821/original/file-20170607-25764-pbljrg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/172821/original/file-20170607-25764-pbljrg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/172821/original/file-20170607-25764-pbljrg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/172821/original/file-20170607-25764-pbljrg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/172821/original/file-20170607-25764-pbljrg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/172821/original/file-20170607-25764-pbljrg.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">For now, most BCI technology relies on somewhat cumbersome EEG hardware that is definitely not stealth.</span>
<span class="attribution"><span class="source">Mark Stone, University of Washington</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Imagine that instead of using a P300 signal to solve the mystery of a “stolen” item in the lab, someone used this technology to extract information about what month you were born or which bank you use – without your telling them. Our research group has <a href="https://digital.lib.washington.edu/researchworks/handle/1773/33808">collected data suggesting this is possible</a>. Just using an individual’s brain activity – specifically, their P300 response – we could determine a subject’s preferences for things like favorite coffee brand or favorite sports.</p>
<p>But we could do it only when subject-specific training data were available. What if we could figure out someone’s preferences without previous knowledge of their brain signal patterns? Without the need for training, users could simply put on a device and go, skipping the step of loading a personal training profile or spending time in calibration. Research on trained and untrained devices is the subject of <a href="http://brl.ee.washington.edu/neural-engineering/bci-security/">continuing experiments at the University of Washington</a> <a href="https://perso.uclouvain.be/fstandae/PUBLIS/190.pdf">and elsewhere</a>. </p>
<p>It’s when the technology is able to “read” someone’s mind who isn’t actively cooperating that ethical issues become particularly pressing. After all, we willingly trade bits of our privacy all the time – when we open our mouths to have conversations or use GPS devices that allow companies to collect data about us. But in these cases we consent to sharing what’s in our minds. The difference with next-generation P300 technology under development is that the protection consent gives us may get bypassed altogether.</p>
<p>What if it’s possible to decode what you’re thinking or planning without you even knowing? Will you feel violated? Will you feel a loss of control? Privacy implications may be wide-ranging. Maybe advertisers could know your preferred brands and send you personalized ads – which may be convenient or creepy. Or maybe malicious entities could determine where you bank and your account’s PIN – which would be alarming. </p>
<h2>With great power comes great responsibility</h2>
<p>The potential ability to determine individuals’ preferences and personal information using their own brain signals has spawned a number of difficult but pressing questions: Should we be able to keep our neural signals private? That is, should neural security <a href="https://doi.org/10.1186/s40504-017-0050-1">be a human right</a>? How do we <a href="https://dx.doi.org/10.2139/ssrn.2427564">adequately protect and store all the neural data</a> being recorded for research, and soon for leisure? How do consumers know if any protective or anonymization measures are being made with their neural data? As of now, neural data collected for commercial uses are not subject to the same legal protections covering <a href="https://www.hhs.gov/hipaa/index.html">biomedical research or health care</a>. Should neural data be treated differently?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/172822/original/file-20170607-25764-qhx5o4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/172822/original/file-20170607-25764-qhx5o4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/172822/original/file-20170607-25764-qhx5o4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/172822/original/file-20170607-25764-qhx5o4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/172822/original/file-20170607-25764-qhx5o4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/172822/original/file-20170607-25764-qhx5o4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/172822/original/file-20170607-25764-qhx5o4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/172822/original/file-20170607-25764-qhx5o4.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">Neuroethicists from the UW Philosophy department discuss issues related to neural implants.</span>
<span class="attribution"><span class="source">Mark Stone, University of Washington</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>These are the kinds of conundrums that are best addressed by neural engineers and ethicists working together. Putting ethicists in labs alongside engineers – <a href="http://www.csne-erc.org/research/neuroethics">as we have done at the CSNE</a> – is one way to ensure that privacy and security risks of neurotechnology, as well as other ethically important issues, are an active part of the research process instead of an afterthought. For instance, Tim Brown, an ethicist at the CSNE, is “housed” within a neural engineering research lab, allowing him to have daily conversations with researchers about ethical concerns. He’s also easily able to interact with – and, in fact, interview – research subjects about their <a href="http://www.csne-erc.org/engage-enable/post/ethics-cornerstone-neural-engineering-research">ethical concerns about brain research</a>. </p>
<p>There are important ethical and legal lessons to be drawn about technology and privacy from other areas, such as <a href="https://www.genome.gov/27561246/privacy-in-genomics">genetics</a> and <a href="http://www.theneuroethicsblog.com/2011/08/ethical-dimenstions-of-neuromarketing.html">neuromarketing</a>. But there seems to be something important and different about reading neural data. They’re more intimately connected to the mind and who we take ourselves to be. As such, ethical issues raised by BCI demand special attention.</p>
<h2>Working on ethics while tech’s in its infancy</h2>
<p>As we wrestle with how to address these privacy and security issues, there are two features of current P300 technology that will buy us time.</p>
<p>First, most commercial devices available use dry electrodes, which rely solely on skin contact to conduct electrical signals. This technology is prone to a low signal-to-noise ratio, meaning that we can extract only relatively basic forms of information from users. The brain signals we record are known to be highly variable (even for the same person) due to things like electrode movement and the constantly changing nature of brain signals themselves. Second, electrodes are not always in ideal locations to record.</p>
<p>All together, this inherent lack of reliability means that BCI devices are not nearly as ubiquitous today as they may be in the future. As electrode hardware and signal processing continue to improve, it will be easier to continuously use devices like these, and make it easier to extract personal information from an unknowing individual as well. The safest advice would be to not use these devices at all.</p>
<p>The goal should be that the ethical standards and the technology will mature together to ensure future BCI users are confident their privacy is being protected as they use these kinds of devices. It’s a rare opportunity for scientists, engineers, ethicists and eventually regulators to work together to create even better products than were originally dreamed of in science fiction.</p><img src="https://counter.theconversation.com/content/77759/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eran Klein a member of the Center for Sensorimotor Neural Engineering (CSNE) at the University of Washington which receives funding from the National Science Foundation (NSF).</span></em></p><p class="fine-print"><em><span>Katherine Pratt works for the Electrical Engineering department at the University of Washington in Seattle, and is affiliated with the Center for Sensorimotor Neural Engineering (CSNE). Katherine Pratt receives funding from the National Science Foundation and Technology Policy Lab, and has also previously received support from Google. The CSNE partners with the companies listed at <a href="http://csne-erc.org/content/current-members">http://csne-erc.org/content/current-members</a></span></em></p>BCI devices that read minds and act on intentions can change lives for the better. But they could also be put to nefarious use in the not-too-distant future. Now’s the time to think about risks.Eran Klein, Adjunct Assistant Professor of Neurology at Oregon Health and Sciences University and Affiliate Assistant Professor of Philosophy, University of WashingtonKatherine Pratt, Ph.D. Student in Electrical Engineering, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.