The term area d23 refers to one of four parts of the dorsal posterior cingulate cortex.The other parts are area 23d of Vogt, area 23c of Vogt, and area d31. In the human it is located in the posterior cingulate gyrus dorsal to the splenium of the corpus callosum. It is caudal to area 23d of Vogt, ventromedial to area d31, and dorsal to area v23 of the ventral posterior cingulate cortex. It has two parts: area d23a and area d23b. Its location in the macaque is similar, except that it borders the entire area 31 ( Vogt-2012 ). It may have partial equivalence to the cingulate/retrosplenial cortex of the rat ( Swanson-2004 ) and the mouse ( Hof-2000 ).