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From Alzheimer’s to smart pills, cognitive science explained

Pills for kicks. arenamontanus, CC BY-NC

Jason Shepherd, assistant professor of neurobiology and anatomy at the University of Utah answered questions posed by the public on Reddit. The Conversation has curated the highlights.

Cognitive disorders

What are the chances of a cure for Alzheimer’s within the next decade?

I’m actually quite optimistic that there will be a viable and mechanistic treatment for Alzheimer’s disease (AD) in the next ten years. One major challenge is being able identify and diagnose people with AD much earlier than when they first present with symptoms because research is showing that even we had a drug that treats the root cause of AD … Giving people the drug at the late stages of the disease cannot reverse the damage done already. So people are searching for a simple blood test or diagnostic that will help identify who needs treatment very early on. Indeed, many of the current AD trials have failed because of this I believe.

They are now testing current therapies in a large trial in families who have a genetic form of AD where they give them the drug early, before symptoms are evident. It will take years to evaluate the outcomes but this will be an important validation of the current leading hypothesis (amyloid cascade theory).

How likely is it that diseases like autism, schizophrenia, and Alzheimer’s could potentially be influenced by viruses, bacteria, or parasites that we currently don’t recognise or understand? For instance, I’m thinking of something like Toxoplasma gondii.

So far in very rare cases, viruses and bacteria have been known to cause symptoms that are reminscent of some of these diseases. However, they are usually associated with very quick onset of symptoms and rapid decline in function. So far there isn’t any evidence that a common virus is a major cause of neurological disorders. But gut in the bacteria is a fascinating area of research right now and many studies are finding that there is a big link between the gut flora and behaviour. The jury is out on whether they contribute to common neurological disorders but this is a fascinating area that may end up being very important to brain function.

One thing I will point out is that many of these neurodegenerative diseases have aggregation of proteins that are toxic to the brain. Scientists are trying to find ways of either reducing the aggregates or preventing them from forming the oligomeric intermediates that seem to affect brain function. The hope is that treatments that affect these processes could be beneficial for many of these diseases.

What current scientific advancements with regard to cognitive disorders should we be excited about?

I think one of the most exciting new areas is in the realm of genetics. It has become so cheap to sequence people’s genomes that large studies can now be conducted to look for the genetic contribution to common neurological disorders. Identifying these genes is not only very useful to scientists who want to understand the proteins that may not be working correctly … but it will also allow Doctors in the future to tailor treatments. This has revolutionised Cancer treatment, for example, because some drugs work very well on cancers caused by certain mutations. Right now we have been limited to diagnosing brain disorders purely on symptoms alone.

Brain science

How much of our behaviour is determined by environmental impacts like diet, sleep or toxins?

My particular research area of interest is in fact investigating how the environment and experience modifies the brain at the cellular and molecular level. Your brain is initially hardwired by your genes, think of it as a blank computer with new hardware but now needs software to make it run. That software is constantly being updated, via experiences, even in older ages. So diet, sleep or anything else will affect behaviour a great deal. But to be clear, everyone has the hardware and so behaviour is ultimately a complex interplay between genes and experience.

I am surprised to see the hardware/software analogy. Where does the hardware end and the software begin?

It’s a somewhat over-used analogy but easy for people to understand. There’s obviously no clear divide but one can think of wiring/anatomy as being the hardware set by your genes. All human brains have pretty much the same connections, regions etc with subtle differences. It’s those subtle differences, though, that are altered by the functional output of the neurons or the “program” that runs on top of the hardware if that makes sense.

What’s your take on nootropics (cognitive enhancers) in general?

This is going to become more and more of an issue as we understand how to enhance the capacity of the brain to learn even in normal people. The law and ethics committees need to be set up in conjunction with scientists and clinicians. Caffeine is the most common drug in the world and it’s a nootropic (see this recent study). Each drug will have to be evaluated on its own merit and what sort of side effects come with it.

Do you think smoking marijuana has a long-term negative effect on our brain chemistry and memory?

This is certainly a pertinent topic right now. There are fairly good studies both in humans and in animals showing that chronic use of marijuana, especially in adolescents can lead to cognitive decline especially in working memory. Whether this is also applicable to adults who chronically smoke, it’s less clear. Legalising the drug has pros and cons, but I worry that increased access to the drug in teenagers will have long term consequences, let alone the fact that smoking is just bad for you in general. I just think we don’t know enough about exactly how chronic use will affect cognition. Scientists also need to figure out how much intake is bad or will lead to permanent effects.

Someone asked about alcohol consumption. Chronic alcoholism is extremely bad for the brain, causing all sorts of damage. It’s unclear what moderate alcohol intake does … most studies that look at this are not well controlled.

What’s your take on free will?

It’s a tough question and hard to really answer concretely. My take is that we all have free will to a degree but if your brain is damaged in some way … the choices you make are constrained so you may have limited free will. I find this topic fascinating because it has huge implications for the law, for example. Are psychopaths driven to make the decisions they do outside of normal free will? Is their brain just wired so differently that they have no other choice? If so, are they then culpable? These are insights that Neuroscience is going to offer I think and society will have to figure out how to deal with it from a law/ethics perspective.

Are you optimistic that advances in neuroscience will bridge the gap between the age old “Mind-Body Problem”?

Yes, just like chemistry and physic have been united, so can the different levels of analysis in neuroscience. It’s not going to be easy but I think it’s a great challenge. Of course, the usefulness of the explanations depends on what the question of study is.

Could you explain some pitfalls and common mistakes people make when investigating evolutionary adaptations in cognitive psychology?

Personally I’m not a huge fan of evolutionary psychology because I find most of them are “just so” stories that are interesting explanations but hard to really verify or test as scientific hypotheses. But clearly the brain evolved and so did its function so I think a better approach, which most scientists do now, is to use comparative approaches by studying many different animal brains.

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