The term area 32o refers to the portion of area 32 in anterior cingulate cortex of the human, macaque, rat and mouse. Topologically, in the human, it coincides approximately with the superior rostral gyrus and inferior rostral gyrus, which lie rostral to the anterior cingulate gyrus and subcallosal gyrus. Architectonically it is the largest and most rostral part of anterior cingulate cortex. Together with area 32pr of midcingulate cortex, it forms area 32, which is coincident with the original area 32 of Brodmann (human) ( Vogt-2012 ). Dorsally it is bounded by area 9 and continuous with area 32pr. It is bounded caudoventrally by area 25, rostrally by area 10 and ventrally by area 14 ( Petrides-2012 ). It has three parts. From dorsal to ventral, they are area 32d, area 32p and area 32s. In the macaque it is located topologically in a rostral extension of the anterior cingulate gyrus. Architectonically it is similar to the human except that the macaque lacks an area 32d, and the dorsal boundary is with area 24c.. Topologically, in the rat and mouse it forms the rostral pole of cerebral cortex and is located in the prelimbic area, the infralimbic area and the medial orbital area ( Swanson-2004; Hof-2000 ). Architectonically its caudal boundary is with area 24a ventrally and area 24b dorsally. Like the macaque, the rodents lack an area 24c ( Vogt-2013 ). While original sources name the area simply '32' ( Vogt-2012; Ongur-2003 ), in NeuroNames it is named '32o' to eliminate ambiguity with the larger area 32 as defined in Brodmann-1909.