David W. Perry
Alan C. Evans
Robert J. Zatorre
Dept. of Neuropsychol., McGill Univ., 3801 University St., Montreal, PQ H3G 2B4, Canada
Although much is known about the auditory nervous system, in both man and nonhuman primates, and about the neural substrates for vocal production, particularly in nonhuman primates, relatively little is known about how these two systems are integrated in vocal behavior. The present study used positron emission tomography with magnetic resonance imaging to investigate regional changes in blood flow during the performance of a rudimentary singing task by 12 healthy right-handed volunteers. When activation during the repetetive singing of a single target pitch was compared to that during passive auditory stimulation with complex tones in the same frequency range, a widely distributed network of activated brain regions was observed. Some regions of activation were plausibly explained by the auditory stimulation of self-vocalization (right medial geniculate body and right primary auditory cortex), while others were clearly related to the act of vocalization (periaqueductal grey, subcallosal anterior cingulate gyrus, supplementary motor area, cerebellum and primary motor face region, bilaterally). Finally, the neuroanatomical connections of the mid-dorsal insula, activated bilaterally, and of the dorsomedial thalamus are suggestive of a particular role in auditory-vocal integration. It is proposed that auditory-vocal integration, both in singing and in speech, involves complex neural interconnections between many of the above regions.