A recent study conducted at the University of Zurich's Divison of Neuropsychology determined that the brain regions associated with musical ability span from the motor cortex, auditory cortex to the cerebellum. Professional and non-professional musicians were studied over a 15 year period to demonstrate that neuroplasticity is associated with musical practice. Short term musical training has been shown to activate many brain regions, and long after training has stopped, we still find elevated levels of brain plasticity.
"Nearly all of those brain areas involved in the control of musical expertise (motor cortex, auditory cortex, cerebellum, and other areas) show specific anatomical and functional features in professional and semi-professional musicians." -Lutz Jancke, Division of Neuropsychology, Psychological Institute, University of Zurich