The term area v23 refers to one of two parts of the ventral posterior cingulate cortex.The other is area v31. In the human it is located in the posterior cingulate gyrus caudal to the splenium of the corpus callosum. It is rostroventral to area v31 and caudoventral to area d23 of the dorsal posterior cingulate cortex. It is divided into two parts: area v23a and area v23b. Its location in the macaque is similar except that the macaque has no area v31. Thus, in the macaque it constitutes the entirety of the ventral posterior cingulate cortex ( Vogt-2012 ). It may have partial equivalence to the retrosplenial area of the rat ( Swanson-2004 ) and the mouse ( Hof-2000 ).