Noradrenergic regulation of the basolateral amygdala

The biogenic amine norepinephrine (NE) is synthesized in a small, heterogeneous population of brain stem neurons that project throughout the central nervous system. Although NE was originally thought to serve primarily as an arousal signal, it is now widely recognized as a critical mediator of emotional influences on a broad range of behavioral and cognitive tasks. Importantly, a growing body of evidence suggests that dysregulation of brain NE signaling contributes to many neurological disorders, including anxiety and stressor disorders, depression, as well as neurodegenerative disorders like Parkinson's disease and Alzheimer's. While many NE circuits contribute to its diverse roles in normal and pathological brain function, NE innervation of the basolateral amygdala (BLA) has received considerable attention, particularly in encoding the influences of negative affect on cognitive processing. Early evidence suggested that NE signaling in the BLA played a central role in promoting the enhancement of fear-related memories and more recent findings suggest that alterations in BLA NE signaling may drive maladaptive phenotypes associated with affective disorders like PTSD. The goal of this chapter is to review the literature describing the role of BLA NE signaling in the healthy and diseased state with a focus on illuminating potential therapeutic avenues.