Organization of the forepaw representation in ferret somatosensory cortex

Little is known about the function and structure of ferret somatosensory co rtex. We used anatomical methods and multi-unit recordings to characterize the cytoarchitecture, functional responses and topography of the forepaw re presentation in ferret somatosensory cortex. The representation of the cuta neous ferret forepaw encompasses approximately the caudal half of the poste rior sigmoid gyrus. The posterior sigmoid gyms and coronal sulcus contain u nique cytoarchitectonic fields that conform in large part to earlier descri ptions of somatosensory regions in the cat. The cytoarchitectonic regions f orm mediolateral bands that comprise areas 4, 3a, 3b, 1, and 2 (from rostra l to caudal). We studied most extensively areas 3a and 3b for functional re sponses to somatic stimuli; our data indicate that ferret somatosensory cor tex contains at least two representations of the forepaw in these two areas . Our data also suggest that within ferret somatosensory cortex, the morpho logical and submodality features gradually, rather than abruptly, distingui sh themselves as unique cortical fields.