Complex and widespread activation in many brain areas is seen while performing, listening or mentally imaging music, activity that varies with training, previous exposure, personal preference, emotional involvement and many other factors. Playing a musical instrument demands extensive motor and cognitive abilities, and early musical learning results in plastic reorganization of the developing brain – one example being the increased cortical representation area for the left little finger in (right-handed) string-players, which correlates with age at the start of training. Even though the developing brain has the most pronounced changes, the adult healthy brain has a considerable plasticity. Conductors have superior spatial tuning compared with non-musicians and pianists. Attentive listening to music for as little as three hours can temporarily alter the auditory cortex. Interactions between genetic predisposition, environment and training play a role in music as in other areas. It has been proposed that musical training may improve other cognitive functions. There is some evidence that this may be the case but it is an area that needs further exploration.