The corpus callosum -- the thick band of nerve fibers connecting the brain' s two hemispheres -- of a musician is on average larger than that of a nonmusician  The differences in the size of corpora callosa are particularly striking when adult musicians who began training around the age of seven are compared to adult nonmusicians
Ttherefore, musical training, particularly when it begins at a young age, causes certain anatomic brain changes
Musical training late in life does not cause anatomic changes to the brain.