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 behavioural correlate for such functional specializations, or a division of labour, within auditory cortex is largely unknown. The long-term goal of our research program is to elucidate the behavioral division of labour within cat 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 neuronal activity and cerebral connections, will provide evidence for, or refute, which hierarchical or network theories best explain processing in auditory cortex. In the proposed study, we combine a battery of behavioural tests, electrophysiological recording, and reversible deactivation to dissect the functional plan of auditory cortex. This project will examine the 13 regions of acoustically-responsive cortex: the four tonotopic fields (AI, AAF, PAF VPAF) and nine non-tonotopic areas (AII, FAES, dPE, iPE, vPE, DZ, VAF, IN, T). 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 what processing stream in extrastriate visual cortex. Overall, we plan to produce the first compendium of the multiple, yet unique, combinations of neural contributions each region of auditory cortex makes to the processing of pattern and temporal stimuli. The results from these studies are essential for the development of functionally-based models of cerebral operations that will form the foundation of future knowledge of emergent and higher-order integrative processes.