29. Central Amygdala and Periaqueductal Grey Circuits for Active and Passive Responses to Threat

Behavioral responses to threat encompass evolutionarily conserved active or passive defensive motor responses, such as flight and freezing, respectively. The central nucleus of the amygdala (CEA) and midbrain periaqueductal grey (PAG) are important parts of the circuitry that underlies top-down control of the defense reaction to threat. Defensive action selection has been modelled around the concept of threat imminence, but the circuit mechanisms mediating different defensive behaviors and the switch between them remain unclear.