Cortical substrates for processing auditory feedback during vocalization

Johns Hopkins University, Baltimore MD

Investigators

Abstract

DESCRIPTION (provided by applicant): Human communication relies on hearing sensation to interpret other's speech and to monitor, learn, and maintain one's own speech. Hearing one's own speech through auditory feedback is crucial to maintain normal speech in noisy acoustic environment. Understanding auditory-motor interactions in auditory cortex is essential to understanding the role of hearing in vocalization perception and production. In a phenomenon common to human and non-human primates, neural activity in auditory cortex is suppressed before and during vocalization. This vocalization-induced suppression may reflect a corollary discharge signal involved in cortical representation of one's own voice in a noisy environment or correcting vocal errors. While there is evidence for functional specialization of rostral and laterl regions for processing communication sounds, auditory cortex regions specialized for processing self-produced vocalizations have not been described. Indirect evidence suggests that neurons projecting from premotor cortex activate inhibitory interneurons in auditory cortex, but there is not clear evidence whether this or another pathway delivers vocalization-induced suppression to auditory cortex. Aim 1 will test the hypothesis that neurons in belt and parabelt regions of auditory cortex are preferentially suppressed during vocalization. Aim 2 will test the hypothesis that vocalization-induced suppression in auditory cortex is caused by neural signals from vocalization-related premotor cortex The goal of the proposed research is to further our understanding of the neural substrates for processing auditory feedback during active hearing in the non-human primate brain. Findings from the proposed studies will elucidate the neural circuitry for sensorimotor integration in auditory cortex and help better understand causes of communication disorders such as speech disorders, stuttering, and learning speech in hearing loss and cochlear implant patients.