Fig. 1.

Anatomy of the PMC. (A) PMC (highlighted region in purple), which forms a core node of the default mode network, is located on the medial surface of the brain. (B) The PMC is bounded ventrally by the parieto-occipital sulcus (which divides it from the cuneus); dorsally by the cingulate sulcus (cgs) and its marginal branch (mb); and extends anteriorly to approximately mid-cingulate level before it joins the anterior cingulate cortex. The PMC contains the PCC (areas 23a, 23b, and 23c), RSC (areas 29 and 30), medial parietal cortex (area 7m), and a transitional cortical area 31. The RSC is superficially visible as gyral cortex around areas 29 and 30; however, it extends perisplenially around the corpus callosum (cc) hidden within the callosal sulcus (cs; B and C).