April 2, 2008

The neuroscience of you

This column marks the inception of a weekly attempt to make neuroscience more intellectually accessible to the greater Knox community. Neuroscience is the emerging science of brain function and indeed the closest we can come to describing how we are made (or make ourselves) who we are.

As a coalition of Knox neuroscience students our aims are thus: 1) to provide practical information gleaned from research on how to use our brains better as individuals, 2) to offer up some of the most mystifying and insightful findings about the brain, and 3) to remain open to interpretation of these findings as well as guidance on what to cover from YOU, our readers! The field of neuroscience is growing rapidly as there is still much to learn about our brains, so we would like to know what topics you are interested in learning about. To that end, we’ll soon be sending out a short survey to gauge interest level and topics. But for now, let’s all get on the same page by considering these commonly held myths about the brain:

We only use 10 percent of our brains

Perhaps nowadays this notion is not as pervasive as it once was, but certain New Age circles have made use of it to promote their brand of self-help techniques designed to help enable people to “unlock their full potential”.

Regardless of its marketing value, this statement is patently false. If we only used 10 percent of our brains, why then would have evolution dumped such an energetically expensive organ into our skulls? Why would our skulls have grown big enough to house it? Though the brain accounts for about 2 percent of our body weight, it uses about 20 percent of our total energy while we are at rest.

Neuroimaging studies have revealed that we use all parts of our brain at certain times and never the whole thing at once—so, you could imagine using only 10 percent in any one instant, but then you’d have to imagine using more and less than that at other instants. That being said, if the notion still helps you work towards “personal enlightenment,” then more power to you.

If you do _____, you will kill ___ many neurons.

We’ve all heard that every time you do _____ (be it smoke a joint or head a soccer ball) you will kill ___ many neurons. This is a particularly pernicious myth, since it was probably only propagated to discourage people from doing specific things. Sure, the brain consists of organic tissue and certain activities will indeed destroy living cells, but there is no clear method of telling what kills what. More likely certain activities alter the connectivity, firing patterns, and/or receptor profiles of certain neurons (all of which are to be altered again) before they kill anything. So, rest assured that your brain will survive and read on to the next myth for more elaboration on this.

Our brains don’t change after age ___.

It used to be common doctrine that after a certain age (say infancy, adolescence, or the mid-20s) the brain is fixed in development. Recent advances in neuroscience have identified two important processes that clearly dispel this myth: neuroplasticity and adult neurogenesis.

Neuroplasticity describes the ability of neurons to modify their activities and connections in response to a change in the environment, the body, or another part of the brain. This is the reason why we can learn new things until the day we die that will stick with us forever, and the reason why we can memorize a phone number for the 30 seconds we need it and then forget it. Although the concept is unsurprising given the ever-changing nature of thought, research has shown that these changes occur on an incredibly minute scale.

Adult neurogenesis is more revolutionary because up until around 20 years ago, the medical world firmly believed that we are born with all the neurons we will ever have. As you can imagine, this notion held dire consequences for recovery from brain injury and the treatments for such. Now it’s been proven that our brains produce new neurons well into adulthood, and that specific lifestyle factors (such as exercise) influence whether and where these new neurons become integrated into existing circuitry. Though a few neurogenic areas have been identified, the most significant thus far is the hippocampus, a critical structure for forming long-term memory. So the idea is that if you exercise, you’ll have better memory and help ward off some of the detrimental cognitive effects of aging.

Left-brained and right-brained people exist.

So there’s a Facebook application that, after a series of questions, identifies people as either right-brained or left-brained. Allow me to offer a resounding, “Damn you, Facebook!” Apparently, creative “artsy” people are right-brained and logical “scientific” individuals are left-brained, meaning they use that hemisphere of their brain preferentially. Is this to say that right-brained people are not rational or left-brained people are not creative? There are many reasons why this view is problematic.

First off, let’s talk about the origin of this distinction. Split-brain research (in which doctors would sever the central connection between the two hemispheres in humans) began in the 1950s as a treatment for severe cases of epilepsy. After testing these patients, researchers found that some of our capabilities seemed to be housed in one hemisphere or the other. For example, in most people (who are right-handed), the left hemisphere is the site of most language processing. Furthermore, language is considered to be our most “lateralized” function—meaning that the brain activity that gives rise to it occurs predominantly in one hemisphere over the other. So the fact is, all of our mental faculties make use of brain areas in both hemispheres, often at the same time.

While this distinction can be instructive when it comes to conceptualizing general lateralization trends in brain function, it is also dangerously reductionistic and indeed personally limiting to pigeonhole oneself into an identity of either “right-brained” or “left-brained”.

Thanks for your attention. You can direct any questions, ideas, or revelations to Andy Arnold.

Andy Arnold

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