The musical mismatch negativity in MEG represents the violation of a regularity in a musical sequence. It may be considered as a pre-attentive sensory change detection or as a top-down prediction error signal. Rhythmic and melodic deviations within a musical sequence elicit a stronger mismatch negativity in musically trained subjects than in novices indicating that acquired musical expertise leads to better discrimination accuracy of musical material and better predictions about upcoming musical events. Expectation violations to musical material could therefore recruit neural generators that reflect top-down processes that are based on musical knowledge.
To investigate the neural generators of musical deviance detection after musical training with rhythmic material we localized musical mismatch data from a previous MEG study with beamformer analysis. The training material focused on rhythmic progression and the MEG measurements on rhythmic violations. The beamformer analysis revealed neural activation bilaterally within the vicinity of auditory cortices and in the inferior parietal lobule, in an area that has recently been implied in temporal processing. We suggest that the musical training that subjects had received prior to the MEG measurement, has established an internal forward model linking a piano tone with a specific motor movement. This internal forward model might have supported and improved predictions about the timing of upcoming tones. Expectation violations were than presumably processed in the parietal lobule where timing and the motor system are closely linked.

mismatch negativity, music, beamforming, MEG