Differential Thickening and Thinning of Auditory Cortex in Deaf Cats Revealed with Ultra-High-Field MRI
Abstract
In the absence of hearing, the brain must adapt and repurpose the former auditory cortex. In this study we scanned normal hearing (n=29) and deaf (n=26) cats to identify cortical areas of differing thickness using the auditory regions from a 3D cortical atlas. Compared to hearing controls, differential thickening and thinning was observed in specific regions of the deaf auditory cortex. More dorsal auditory regions tended to be bilaterally thicker in the deaf group, while more ventral regions in the left hemisphere were thinner. The location and nature of these changes creates a gradient along the dorsoventral axis wherein dorsal auditory cortical fields are thickened while more ventral fields are thinner in deaf animals compared to hearing controls. Whether this reflects the spatial separation between the functionally distinct “where” and "what" pathways, or a more general property of distance along the dorsoventral axis of cortex remains to be examined.