From a study by Patrick Bermudez, Jason P. Lerch, Alan C. Evans, Robert J. Zatorre:
Subject groups were 53 non-musicians and 53 musicians (10 years or more of musical experience, 21 with absolute pitch). T1 MR images were RF inhomogeneity corrected, linearly registered to the MNI152 symmetric template with a 9-parameter transformation and tissue classified. Following these steps, deformable models were used to first fit the white matter surface and then expand outward to find the gray matter/CSF intersection. Cortical thickness is defined as the distance between the linked vertices of the white and gray surfaces. Musician and non-musician thicknesses were then contrasted and evaluated according to the general linear model and significance thresholds established according to the False Discovery Rate theory.
Results & Discussion
The musicians versus non-musician contrast of cortical thickness reveals significantly greater thickness for musicians in the superior temporal surfaces, the motor cortices, broad areas of the prefrontal lobes, the left lingual gyrus and the right parahippocampal gyrus. The auditory and motor cortices have previously been shown to be morphologically distinct in musicians with the use of other techniques [emphasis added]. As a measure, cortical thickness is complimentary yet more specific and constrained than the typical VBM measure which usually conveys information about extent, shape and position concurrently. The mid-dorsolateral frontal areas are thought to be of particular importance in subserving working memory function, an aspect of cognition very heavily relied upon in music perception and production [emphasis added]. The parahippocampal areas are suspected to accept multi-modal input and play important roles in various types of memory formation [emphasis added].
Side View of the Human Brain Showing the Functional Lobes
What this study seems to confirm is that learning to play music exercises the brain, and because music is so complex, certain areas of the brain get a real workout which doesn’t happen in ordinary activities. Playing music demands a specific combination of skills which then are more fully used, either individually or in combination, in other activities. This may be why the results are contradictory in some other studies, but it’s clear that these are transferable skills to other situations, which explains the better test-taking skills, better grades, better college and medical school acceptance, and success in many other activities.
See the Neuroanatomy page for an explanation of what the various affected parts of the brain do.