Grant: Discovery Grants Program - Individual

Functional specialization is a common characteristic of the cerebral cortex. Globally, regions are specialized to perform particular sensory or motor functions. Within extrastriate visual cortex of humans, monkeys and cats, areas have been identified that are further specialized for spatial, motion, and pattern processing. The behavioral correlate for such functional specializations, or a ""division of labor"", within auditory cortex is largely unknown. The long-term goal of the proposed work is to elucidate the behavioral ""division of labor"" within auditory cortex and determine the relative contributions that the different auditory fields make to acoustically-mediated behaviors. These results, when combined with investigations of underlying cerebral connections, will provide evidence for, or refute, which hierarchical or network theories best explain processing in auditory cortex. In the present study, we will combine a battery of behavioral tests, reversible deactivation, and electrophysiological recording, to dissect the functional plan of auditory cortex. In the proposed experiments we will emphasize pattern and temporal processing in auditory cortex. We hypothesize that the use of the proposed tasks and stimuli will reveal, both behaviorally and electrophysiologically, that areas along the dorso-ventral plane have increasing stimulus specificity similar to that of the ventral processing stream in extrastriate visual cortex. Overall, we will produce the first compendium of the multiple, yet unique, combinations of neural contributions each region of auditory cortex makes to acoustic pattern and temporal discriminations. In addition to the extensive behavioural projects to be undertaken, we will also use similar stimuli to evoke responses in individual cortical areas while we reversibly deactivate flanking areas to determine the functional contributions that different regions of non-primary auditory cortex make to one another. These electrophysiological investigations will directly address the possible existence of cortical processing streams in non-primary auditory cortex.