Sam Wang, neuroscientist at Princeton University, debunks common brain myths and discusses his book, ‘Welcome to Your Brain.’
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Sam Wang on Common Brain Myths Topic: Sam Wang on the 10% myth The 10% myth is a funny one because it doesn’t come from an identifiable neuroscientific discovery. The earliest mention of the idea that you only use 10% of your brain comes from the motivational speaker and writer Dale Carnegie in “How to Win Friends and Influence People.” Actually, Lowell Thomas said in the preface. And before that, the only statement that resembles that is again, as I mention before, this pioneer of psychology and as it turns out neuroscience, William James. He told audiences that we only meet a fraction of our full potential. And I think that statement is true because it certainly the case, for instance, that IQ scores have gone up a few points per decade in modern times, which suggest that there’s some influence in the environment on what we can become. In that sense, we maybe still are exploring our full potential. But the 10% idea is literally not true. If any part of the brain is damage, it can lead to deficit as a function. For instance, if a person experiences damage to the cerebellum, which guides smooth movements, then people are unable to move smoothly, unable to learn new things like a dance step or a tennis stroke. And you can come up with similar kinds of observations for all parts of the brain so you really need the whole thing. You need a 100% of your brain. If any part of your brain went missing in action, you would notice and you’d be sorry. Well, actually depending on the part of the brain, you might not be sorry. Topic: Sam Wang on alcohol and the brain A really common belief about the brain that you hear at parties is the idea that drinking alcohol kills brain cells. People make light to this all the time. The truth is that alcohol can damage the brain but it’s highly unlikely to kill brain cells. When people look at the brains of alcoholics’ postmortem, it takes decades of drinking before loss of brain cells becomes apparent, okay? And in fact, loss of brain cells, when it does eventually happen, it’s associated with a profound loss of memory, a thing called Korsakoff’s syndrome. And that happens after decades of drinking. Now, having been said, alcohol does cause damage to the brain. So one thing that has been observed is that heavy drinking for years does lead to shrinkage of the brain, and that is probably the source of the idea that alcohol kills brain cells that you can observe shrinkage of the brain. Now, let’s put these two together. Alcohol causes shrinkage of the brain but the cells don’t diminish the number so what that suggest is there something about each individual cell that shrinking. And what’s believed is that the trees, the dendritic trees that neurons have, may retract a little bit and they’re constantly growing and shrinking. And so, what’s believed is that, perhaps, they retracted a little bit. And the practical implication of this is that if you stop drinking, then they, perhaps, will grow back. Okay. So that’s the practical implication. And so, even though the idea is a myth, it’s still important to remember that drinking alcohol is not a good thing for your brain when you do it for many years at a time. I have more that I forgot to give so can I fill that in? The other side of the coin is that moderate amounts of alcohol are not harmful and, in some cases, can even be helpful. And there’s a very specific case, which is red wine. It turns out that moderate amounts of red wine seem to have some kind of protective effect on brain function especially as you are getting older. And it’s not known exactly why but there’s a general principle, which is that things that are good for your heart and your cardiovascular system are also good for your brain. And so, there are health benefits that have been demonstrated of red wine, some of which are mediated through the compound resveratrol. And what’s been observed is that up to 3 glasses of red wine per day for men and up to 2 glasses for women is either neutral o
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