Spatial organization of EEG coherence during listening to consonant and dissonant chords.
Theories of harmony state that the contribution of both sensory and cognitive components is important for musical consonance perception. The aims of the present study were to analyze (a) functional intra- and inter-hemispheric connectivity associated with listening to consonant and dissonant chords using EEG coherence method; (b) relationships between affective responsiveness, sensory aspects of perceived consonance and associated brain connectivity. We identified two lines of inter-hemispheric connectivity in the theta band; one localized anterior being sensitive to consonance and one localized posterior sensitive to dissonance. Stronger right intra-hemispheric connectivity for consonance than dissonance in the theta band was associated with higher pleasantness ratings. The relationship between sensory aspects of perceived consonance and left intra-hemispheric connectivity found in theta-2 was interpreted as processing of vertical harmony without emotional involvement. The stronger connectivity along the axis "left anterior-right posterior" for dissonance than consonance in the alpha-1 band is discussed as a correlate of novelty processing. By introducing a "auditory object dissociation" hypothesis we suggest to extend the present concept of harmony perception. We believe that "auditory object dissociation" is a component of "sensory dissonance."