The effect of musical experience on hemispheric lateralization in musical feature processing.

Music consists of a variety of spectral and temporal features. Generally, brain processing of these features is reported as being right hemisphere dominant. However, there are contradicting results as to whether musical experience affects hemispheric laterality or not. In the present study, we investigated the effect of musical experience on hemispheric lateralization of musical feature processing using magnetoencephalography (MEG). Mismatch fields (MMFs) were measured from 8 musicians and 8 nonmusicians in oddball tasks with four different musical features, including pitch, chord, timbre and rhythm. Regardless of the features, the MMFs showed right-hemispheric dominance in nonmusicians, whereas musicians showed symmetrical MMF amplitudes in both hemispheres. The electrical activity around the auditory cortex to the MMFs also supported the right-hemispheric dominance in nonmusicians and bilateral activation in musicians. Voxel-based morphometry did not detect any group differences around the auditory cortices. These results suggest that musical training changes the hemispheric roles for musical feature processing in the pre-attentive stage, and this functional alteration can occur without apparent anatomical changes.