This project initiates a long-term research program to address the role of the auditory cortex in spatial learning. The PI plans to use functional magnetic imaging (fMRI) techniques to examine the organization of the auditory cortex in cats, and will also conduct concurrent and parallel fMRI and psychophysical studies examining the responses to auditory stimuli in humans. The proposed work will focus on the discrimination of spatial auditory cues using a combination of direct animal experimentation (examining the physiological mechanisms mediating spatial audition) with behavioral and psychophysical studies in humans. The pattern of sensitivity to multiple stimulus manipulations (e.g. tone frequency, level, and ear of presentation) will be used to distinguish functionally distinct fields within the auditory cortex, and detailed "maps" of candidate auditory cortical fields will be created. In the cat, such maps can be directly compared to existing data on the anatomical and physiological organization of fields within the auditory cortex. Comparison of cat fMRI data with that from humans will lead to hypotheses regarding homologous auditory cortex fields and corresponding hypotheses regarding the functional roles of these candidate fields. The existence of fields specialized for auditory spatial processing will be addressed further through psychophysical investigations of human spatial hearing combined with fMRI studies in the same individuals. Integrating these approaches will simultaneously improve the understanding of auditory organization and the role that specific auditory cortical fields play in spatial processing. The proposed research will broadly impact the field of auditory neuroimaging by developing techniques for mapping the field structure of auditory cortex and for presenting spatialized sound in an MRI scanner. The proposed research will also provside research opportunities for undergraduate and graduate students as well as educational opportunities, exposing a wide range of students to neuroimaging in hearing science.
