Spatial Organization of Multisensory Responses in Temporal Association Cortex

Neurons in sensory cortices are often topographically organized according to their response preferences. We here show that such an organization of response preferences also exists in multisensory association cortex. Using electrophysiological mappings we probed the modality preference to auditory and visual stimuli of neurons in the superior temporal association cortex of non-human primates. We found that neurons preferring the same modality (auditory or visual) often co-occur in close spatial proximity, or occur intermingled with bimodal neurons. Neurons preferring different modalities, in contrast, occur spatially separated. This organization at the scale of individual neurons leads to extended patches of same modality preference when analyzed at the scale of millimeters, revealing larger scale regions that preferentially respond to the same modality. In addition, we find that neurons exhibiting signs of multisensory interactions, such as super- or sub-additive response summation, also occur in spatial clus ters. Together, these results reveal a spatial organization of modality preferences in a higher association cortex, and lend support to the notion that topographical organizations might serve as a general principle of integrating information within and across the sensory modalities