Re: Why do humans only use 1 of 10 neurons at a time?

If I'm reading your question right, you are asking about a common myth, for which no scientific evidence exists. We commonly hear that we "only use 1% (or 5% or 10%) of our brain." I've even heard people say that Einstein used 4% while the rest of us only use 1 or 2%, which is why he was a genius! But this sort of thing is almost without a doubt false. First of all, the brain is very expensive to maintain from an evolutionary point of view. There is no way that we would have evolved such a large and resource-demanding organ if we had no use for it. Look at the size of the brains of reptiles and birds. They are tiny, but those animals survive just fine. If we didn't need our big brains, we wouldn't have them.

I suspect that this myth got started because there are so many parts of the brain whose functions are unknown. Analogous to the so-called "junk DNA," scientists and the public have figured that maybe we don't use a lot of our brain, because we can't figure out what many parts do and people seem to do all right even when those parts get damaged. If I've misinterpreted your question and you are actually asking about something more complex, you'll have to resubmit your question with some supporting data that makes you think we might only use 10% of our neurons at any given time.

Joe Simpson
MD/PhD Student, Neurosciences Program
 School of Medicine
St. Louis, Missouri, USA