The term area 24 refers to a part of cingulate cortex that, in the human and the macaque, forms an arc around the the genu of the corpus callosum. In human its outer border extends horizontally along the superior frontal gyrus dorsal to the cingulate sulcus. It is bounded internally by area 33, externally by area 32o, caudally by area 23, and rostrally, beneath the genu of the corpus callosum, by area 25. Equivalent to area 24 of Brodmann (human), it is a composite of three main subareas located in anterior cingulate cortex (ACC), anterior midcingulate cortex (aMCC) and posterior midcingulate cortex (pMCC). The part in ACC is further subdivided, in order from corpus callosum rostrally, into area 24a, area 24b, and area 24c; the part in aMCC is subdivided from corpus callosum dorsally into area a24a', area a24b' and area a24c'; and the part in pMCC is subdivided into area p24a', area p24b', area p24d ( Vogt-2012 ) and area p24c' ( Vogt-2016 ). In the macaque, the area is located similarly. Its location relative to other cytoarchitecturally defined areas is similar to that of the human, except that the macaque lacks an area 33 in that region, so its inner boundary is directly with the corpus callosum deep in the callosal sulcus. It is equivalent to area 24 of Brodmann (guenon). In the rat and mouse the location and organization are similar, but the area is considerably less differentiated. The part in ACC is composed of area 24a and area 24b and MCC is not divided into anterior and posterior parts, so the sole subdivisions there are area 24a' and area 24b' ( Vogt-2013 ).