Different regions of the cerebral cortex are functionally specialized to perform particular sensory or motor functions. Within the visual cortex of humans, and other animals, 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 acoustic behaviors. This project will examine twelve commonly recognized regions of acoustically-responsive cortex: four tonotopically organized fields and eight non-tonotopic areas. Two general classes of tasks will be used to determine if areas specialized for "spatial and motion" or "pattern and temporal" processing can be identified. To make these determinations, cooling loops, which induce localized hypothermia, will be placed in contact with specific regions of the cerebral cortex to effect temporary and reversible deactivation. The final project will examine the structural and functional characteristics of cortical projections to the superior colliculus. The superior colliculus is a midbrain structure that is critical for the accurate directing of head and eyes to visual and acoustic stimuli. Therefore, it is hypothesized that cerebral regions involved in spatial localization of acoustic stimuli will have dense projections to the superior colliculus. These behavioral 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. Over the course of these projects, many graduate students, as well as approximately 50 undergraduate students will be exposed to behavioral testing and histological procedures. Most trainees involved in these projects will be female or from groups typically underrepresented in science. Each semester, students in the lab visit local high schools to discuss their work and make presentations on brain structure and function to psychology classes.
