Speech sounds are the most important sounds that we hear, yet little is known about how these stimuli are represented within human cerebral cortex. The goal of our research is to understand the functional organizations and connections of those areas of human cerebral cortex that are engaged in sound processing and examine how speech sound stimuli are represented within these regions. These experiments involve direct electrophysiological recording from and electrical stimulation of the cerebral cortex of awake human subjects undergoing clinical evaluation of intractable epilepsy. In the course of our investigations we plan to: 1) identify temporal/parietal/frontal brain regions engaged in sound processing, 2) examine their functional interconnections, 3) study the manner in which speech sounds are represented within these cortical regions, and 4) investigate the cortical processes involved in the bimodal integration of auditory-visual speech stimuli. These objectives will be pursued by a multidisciplinary team using state-of-the-art research methods, alone and in combination, to gather complementary sets of human physiological and anatomical data that could not be obtained in the past. We pursue these objectives believing that knowledge of the fundamental structure and function of the normal auditory system is essential to understanding mechanisms that underly impairment of all aspects of hearing, speech, and language.