Neural mechanisms of musical syntax and tonality, and the effect of musicianship.

The neural basis for the processing of musical syntax has previously been examined almost exclusively in classical tonal music, which is characterized by strictly organized hierarchical structure. The present study investigated the neural mechanisms for processing musical syntax across genres varying in tonality - classical, impressionist, and atonal music - and, in addition, examined how musicianship modulates such processing. Results showed that, first, the dorsal stream, including bilateral inferior frontal gyrus and superior temporal gyrus, plays a key role in the perception of tonality. Second, right fronto-temporal regions were crucial in allowing musicians to outperform non-musicians in musical syntactic processing; musicians also benefit from a cortical-subcortical network including pallidum and cerebellum, suggesting more auditory-motor interaction in musicians than in non-musicians. Third, left pars triangularis carries out on-line computations independently of tonality and musicianship, whereas right pars triangularis is sensitive to tonality and partly dependent on musicianship. Finally, unlike tonal music, processing of atonal music could not be differentiated from that of scrambled notes, both behaviorally and neurally, even among musicians. The present study highlights the importance of studying varying music genres and experience levels, and provides a better understanding of musical syntax and tonality processing and how such processing is modulated by music experience.