The term area 30 (macaque) refers to an area of cerebral cortex defined on the basis of cytoarchitecture by Nissl stain in the macaque. It is located caudally in the posterior cingulate gyrus and isthmus of the cingulate gyrus, deep in the callosal sulcus where the gyri join the splenium of the corpus callosum. It is located medial to area 29 (macaque). It is topologically equivalent to area 30 of the human, area 30 of Brodmann (human) and to the retrosplenial agranular area of rodents ( Vogt-1987 ).