The term area d23ab refers to a part of posterior cingulate cortex located caudally in the posterior cingulate gyrus. It is separated from the corpus callosum by retrosplenial cortex and bounded caudally by area v23ab, dorsally by area 31pv and rostrally by area 23d. It is considered equivalent to the sum of area d23a and area d23b of Vogt-2009. Defined in the human by multiple criteria, it is fMRI-deactivated in a WORKING MEMORY task and somewhat deactivated in FACES, STORY, and THEORY OF MIND tasks. Other authors have referred to overlapping parts of the same topological area as 23a, 23b, and d23 ( Glasser-2016 ).