FIGURE 4.

Schematic horizontal view of the extended amygdala (EA) continuum showing the composition of brain regions. The central EA extends from the central nucleus of the amygdala through IPAC to the lateral bed nuclei of the stria terminalis (BNST). Central EA surrounds the VP. The medial EA is located medially to the central EA and contains the medial nucleus of the amygdala and the lateral BNST. Glu and dopaminergic neurotransmission in the BNST is involved in the rewarding aspects of drug addiction, while PV interneurons are involved in withdrawal behaviors of dependent subjects. Chronic morphine exposure could significantly alter the gene expression profiles of EA. Glu, Glutamatergic; IPAC, interstitial nucleus of the posterior limb of the anterior commissure; PV, parvalbumin; VP, ventral pallidum