"Remapping occurs regularly throughout the brain in the absence of injury. My favorite examples concern musicians, who have larger auditory cortical representation of musical sounds than do nonmusicians, particularly for the sound of their own instrument, as well as for detecting pitch in speech; the younger the person begins being a musician, the stronger the remapping.15 Such remapping does not require decades of practice, as shown in beautiful work by Alvaro Pascual-Leone at Harvard.16 Nonmusician volunteers learned a five-finger exercise on the piano, which they practiced for two hours a day. Within a few days the amount of motor cortex devoted to the movement of that hand expanded, but the expansion lasted less than a day without further practice. This expansion was probably "Hebbian" in nature, meaning preexisting connections transiently strengthened after repeated use."