CORTICAL PROCESSING MECHANISM FOR VOCALIZATION WITH AUDITORY VERBAL FEEDBACK

To investigate the relationship between motor and sensory speech cente r, cortical activity was examined using PET while normal subjects perc eived their own voice which sounded different to the articulated one. The results showed significant activation in the superior temporal gyr i with absence of activity in the supplementary motor area (SMA). In a previous study we found significant activation in SMA with no activit y in the superior temporal gyrus when normal subjects simply vocalized . Thus, two different cortical pathways for vocalization were delineat ed: programmed pathway in SMA, and pathway with auditory verbal feedba ck. The former is thought to be the mature system in the adult, and th e latter may be related to speech acquisition.