Effects of Harmonic Expectations and Musical Expertise on Auditory Cortical Responses - A Magnetoencephalography Study -

Abstract

however, the effect on the auditory cortex has rarely been examined. The processing of auditory stimuli depends on both afferent and efferent auditory pathways. Behavioral studies have indicated that the chords harmonically related to the preceding context are more rapidly processed than unrelated chords. P2 (the positive auditory-evoked potential at approximately 200 ms) is principally affected by musical experience, and the source of P2 is the associative auditory temporal regions, with additional contributions from the frontal area. Based on anatomical evidence of interconnections between the frontal cortex and the belt and parabelt regions in the auditory cortex, we hypothesized that musical expectations would affect neural activities in the auditory cortex via an efferent pathway. To test this hypothesis, we created five-chord progressions with the third chord manipulated (highly expected, less expected, and unexpected) and measured the auditory-evoked fields (AEFs) of seven musicians and seven non-musicians while they listened to musical stimuli. The results indicated that the highly expected chords elicited shorter N1m (negative AEF at approximately 100 ms) and P2m (a magnetic counterpart of P2) latencies and larger P2m amplitudes in the auditory cortex than the less-expected and unexpected chords. The relations between P2m amplitudes/latencies and harmonic expectations were similar between the groups

however, the results were more remarkable for the musicians than the non-musicians. These findings suggest that auditory cortical processing is enhanced by musical knowledge and long-term training in an efferent pathway, which is reflected by shortened N1m and P2m latencies and enhanced P2m amplitudes in the auditory cortex.

The present study investigated the effects of harmonic expectations and musical expertise on auditory cortical processing using magnetoencephalography (MEG). Numerous studies have demonstrated that musical experiences enhance auditory cortical processing

however, few studies have examined the effect of harmonic expectations on auditory cortical processing. Most studies regarding auditory cortical response enhancement have investigated acoustical sound without harmonic contexts as stimuli. Studies have demonstrated that harmonic expectations are processed in the inferior frontal gyri and elicit an early right anterior negativity (ERAN)