The extended amygdala is a macrostructure in the brain that is involved in reward cognition and defined by connectivity and neurochemical staining.[1][2] It includes the central medial amygdala, sublenticular substantia innominata, and the bed nucleus of the stria terminalis.[1] The boundaries are indistinct in Nissl stained sections.[2]
A macrostructure postulated to integrate many of the functions of this circuit is described by some investigators as the extended amygdala. The extended amygdala is said to comprise several basal forebrain structures that share similar morphology, immunocytochemical features, and connectivity and that are well suited to mediating aspects of reward function; these include the bed nucleus of the stria terminalis, the central medial amygdala, the shell of the NAc, and the sublenticular substantia innominata.