There is large variation in the region's size across different species. In humans it comprises roughly 0.3% of the entire cortical surface whereas in rabbits it is at least 10% and in rats it extends for more than half the cerebrum dorso-ventrally, making it one of the largest cortical regions. On the basis of its microscopic cellular structure it is divided into dysgranular (area 30) and granular (area 29) regions. It has dense reciprocal projections with the visual cortex, postsubiculum (also known as dorsal presubiculum) and with anterior thalamic nuclei and the hippocampus.
Retrosplenial cortex
Piriform cortex
Postrhinal cortex
Barrel cortex
Fusiform body area
Postcentral sulcus
Posterior parietal cortex
Fields of Forel