田中 昌司

Opera is a performing art in which music plays the leading role, and the acting of singers has a synergistic effect with the music. The mirror neuron system represents the neurophysiological mechanism underlying the coupling of perception and action. Mirror neuron activity is modulated by the appropriateness of actions and clarity of intentions, as well as emotional expression and aesthetic values. Therefore, it would be reasonable to assume that an opera performance induces mirror neuron activity in the audience so that the performer effectively shares an <italic>embodied performance</italic> with the audience. However, it is uncertain which aspect of opera performance induces mirror neuron activity. It is hypothesized that although auditory stimuli could induce mirror neuron activity, audiovisual perception of stage performance is the primary inducer of mirror neuron activity. To test this hypothesis, this study sought to correlate opera performance with brain activity as measured by electroencephalography (EEG) in singers while watching an opera performance with sounds or while listening to an aria without visual stimulus. We detected mirror neuron activity by observing that the EEG power in the alpha frequency band (8–13 Hz) was selectively decreased in the frontal-central-parietal area when watching an opera performance. In the auditory condition, however, the alpha-band power did not change relative to the resting condition. This study illustrates that the audiovisual perception of an opera performance engages the mirror neuron system in its audience.

Auditory-sensorimotor coupling is critical for musical performance, during which auditory and somatosensory feedback signals are used to ensure desired outputs. Previous studies reported opercular activation in subjects performing or listening to music. A functional connectivity analysis suggested the parietal operculum (PO) as a connector hub that links auditory, somatosensory, and motor cortical areas. We therefore examined whether this PO network differs between musicians and non-musicians. We analyzed resting-state PO functional connectivity with Heschl's gyrus (HG), the planum temporale (PT), the precentral gyrus (preCG), and the postcentral gyrus (postCG) in 35 musicians and 35 non-musicians. In musicians, the left PO exhibited increased functional connectivity with the ipsilateral HG, PT, preCG, and postCG, whereas the right PO exhibited enhanced functional connectivity with the contralateral HG, preCG, and postCG and the ipsilateral postCG. Direct functional connectivity between an auditory area (the HG or PT) and a sensorimotor area (the preCG or postCG) did not significantly differ between the groups. The PO's functional connectivity with auditory and sensorimotor areas is enhanced in musicians relative to non-musicians. We propose that the PO network facilitates musical performance by mediating multimodal integration for modulating auditory-sensorimotor control.