A recent article caught our attention, and that was a clinical study of the enhancements in brain activity and development of drummers. Yes, drummers specifically were studied, rather than all musicians. Typically you see a more generalized study group from across all instrumentalists - not just drummers.
To paraphrase the conclusion of the study, students who are trained drummers from an early age develop more communication structures across the corpus callosum, which is the structure that separates the right and left hemispheres of the brain. The right side of your brain tends to control your artistic and creative ability, and your left side of your brain controls your analytical ability. Drummers who start training early can more effectively simultaneously engage both their right side and left sides of their brains across the board.
You can read the article here, you can read the actual study here, and below is I think the most important takeaway:
People who play drums regularly for years differ from unmusical people in their brain structure and function. The results of a study by researchers from Bochum suggest that they have fewer, but thicker fibres in the main connecting tract between the two halves of the brain. In addition, their motor brain areas are organised more efficiently. This is the conclusion drawn by a research team headed by Dr. Lara Schlaffke from the Bergmannsheil university clinic in Bochum and Associate Professor Dr. Sebastian Ocklenburg from the biopsychology research unit at Ruhr-Universität Bochum following a study with magnetic resonance imaging (MRI).