One of the most important books ever written about how the brain and nervous system work for playing music (not just the piano) is The Art Of Playing The Piano, A Scientific Approach, by George Kochevitsky, published by Summy-Birchard.
He proved, much to the dismay of the classical world, that all music is played by ear. That it all starts with the signal from the brain and how strong that signal is. A must for anyone how wants to understand the process. His scientific research is impeccable.
Check it out at amazon.com by entering George Kochevitskys name in the book search engine.
Click Here For Kevin Purrone's Summation (PDF)