This Is Your Brain On Jazz: Researchers Use MRI To Study Spontaneity, Creativity

ScienceDaily (Feb. 28, 2008) — A pair of Johns Hopkins and government scientists have discovered that when jazz musicians improvise, their brains turn off areas linked to self-censoring and inhibition, and turn on those that let self-expression flow...

http://www.sciencedaily.com/releases/2008/02/080226213431.htm