The term perifornical area (PFX) refers to a structurally and functionally defined group of neurons variously illustrated as surrounding, dorsal to, or ventral to the postcommissural fornix (pofx) at the level of the ventromedial nucleus (VMH) of the hypothalamus (HYP) ( Smith-1990 ). It is found in the human ( Mai-1997 ), macaque ( Paxinos-2009a ), rat ( Paxinos-2009b ) and mouse ( Franklin-2008 ). It receives major inputs from the amygdala (AMG)...directly from the medial amygdalar nucleus (MEA) and indirectly from the basolateral amygdalar nucleus (BLN) through the central amygdalar nucleus (CEA) ( DeVito-1982; Amaral-1992 ). Electrical stimulation of the PFX produces the cardiovascular component of defensive responses to threatening stimuli ( Smith-1990; Smith-2007 ). It is the part of HYP most involved in sham rage ( Crosby-1962 ) and fear conditioning ( Smith 1990; Pare-2004 ). It is considered the central controller of cardiovascular responses in the instinctive behavioral control system ( Bowden-2021 ). Final 20 Mar 2025.