The term nucleus of the accessory olfactory tract (OLTa) refers to a group of cells in the outer layer of the cerebral cortex ventral to the anterodorsal part of the medial amygdalar nucleus (MEAad), rostral to the anteroventral part of the medial amygdalar nucleus (MEAav) and medial to the periamygdalar cortex (COA) in the rat ( Swanson-1998 ) and the mouse ( Paxinos-2001 ). It is one of five subdivisions of the MEA. The others not mentioned above are the posterodorsal part of the medial amygdalar nucleus (MEApd) and the posteroventral part of the medial amygdalar nucleus (MEApv) ( Swanson-2004 ). A nucleus by the same name but located in a different location relative to neighboring structures is found in the macaque and the human. In the macaque, it is located in proximity to the periamygdalar cortex ( Paxinos-2009a ). In the human, it is located 4 mm rostral to the MEA, where it is surrounded by the anterior amygdalar area (AAA) dorsally, laterally and ventrally and by the periamygdalar cortex medially ( Mai-1997 ). Considerably more structural, physiological and behavioral evidence exists for a robust accessory olfactory system (OLSa) in the rodent than in the primate. Updated 8 Aug 2024.