" Another experiment, conducted by Pascual-Leone when he was a researcher at the National Institutes of Health, provides even more remarkable evidence of the way our patterns of thought affect the anatomy of our brains. Pascual-Leone recruited people who had no experience playing a piano, and he taught them how to play a simple melody consisting of a short series of notes. He then split the participants into two groups. He had the members of one group practice the melody on a keyboard for two hours a day over the next five days. he had the members of the other group sit in front of a keyboard for the same amount of time but only imagine playing the song--without ever touching the keys. Using a technique called transcranial magnetic stimulation, or TMS, Pascual-Leone mapped the brain activity of all the participants before, during, and after the test. he found that the people who had only imagined playing the notes exhibited precisely the same changes in their brains as those who had actually pressed the keys. Their brains had changed in response to actions that took place purely in their imaginations--in response, that is, to their thoughts. Descartes may have been wrong about dualism, but he appears to have been correct in believing that our thoughts can exert a physical influence on, or at least cause a physical reaction in, our brains. We become, neurologically, what we think. (p33) "

― Nicholas Carr