The term area 8Ad refers to the more dorsal of two components of area 8A. In the human it is located posteriorly in the middle frontal gyrus. Defined on the basis of multiple stains, it is bounded rostrally by area 9/46d, caudally by area 6; dorsally by area 8B and ventrally by the other component of area 8A, area 8Av. Its equivalent in the macaque is similarly located with its upper boundary at the superior limb of the arcuate sulcus and its lower boundary partially defined by the principal sulcus ( Petrides-2012 ). As granular prefrontal cortex, it has no equivalent in the rat ( Zilles-2012 ).