The visual cortex of the agouti (Dasyprocta aguti): architectonic subdivisions.

1. We have studied the cytoarchitecture and myeloarchitecture of the agouti's cortical surface that can be activated by visual stimulation. Five architectonic subdivisions that correspond to distinctive visuotopic representations were characterized. 2. The largest portion of the visual cortex is occupied by area 17 which is situated lateral to the cingulate cortex, medial to area 18, posterior to the parietal cortex, and anterior to the agranular retrosplenial cortex. Additionally, four architectonic subdivisions in the extrastriate visual cortex were distinguished, i.e., from medial to lateral: area 18, area 19, anterior lateral area, and temporal posterior area. 3. Along the border of the extrastriate cortex a ring of nonvisual cortical fields was encountered encompassing parietal (somatic sensorial) cortex, temporal anterior and temporal intermediate (auditory) areas, a band of pre-rhinal cortex, and agranular retrosplenial cortex.