The Role of Norepinephrine in Amygdala Dependent Fear Learning and Memory

The extensive knowledge about the significance and connexions of the amygdala with other brain regions emerged in the early XXth century (Gurdjian, 1928). Since then, the seven comprising nuclei of amygdala  corpus amygdaloideum in rats, have been known (Brodal 1947; Cowan et al., 1965). The presence and stereotaxic locations of all nuclei were confirmed later with more contemporary approaches (Paxinos & Franklin, 2001; Mikula et al., 2007). The additional nuclei belonging to the amygdala are established as “extended amygdala” (Fig. 1) that includes also the bed nucleus of the stria terminalis (BNST). However, the majority of studies address the lateral (LA), basolateral (BLA) and central (CeA) amygadala and their role in several emotionally driven responses in organisms. One of the latter responses is the stress and its circuit initiates in locus coeruleus (LC) after a release of norepinephrine (NE) by noradrenergic neurons.