The term area 23d refers to a part of posterior cingulate cortex located in the posterior cingulate gyrus. It is bounded caudally by area 31a and area d23ab, dorsally by area 23c, rostrally by area p24pr and ventrally by retrosplenial cortex. Defined in the human by multiple criteria, it is fMRI-activated in SOCIAL and CUE tasks. It is deactivated in TOOL, FACES, and THEORY OF MIND tasks. It is more activated or deactivated in LANGUAGE tasks depending on the task with which it is compared ( Glasser-2016 ).