The central nucleus of the amygdala and the construction of defensive modes across the threat-imminence continuum

Moscarello and Penzo propose that mutually inhibitory circuits within the central nucleus of the amygdala implement a 'winner-takes-all' mechanism that guides transitions across defensive modes defined by threat-imminence theory. In nature, animals display defensive behaviors that reflect the spatiotemporal distance of threats. Laboratory-based paradigms that elicit specific defensive responses in rodents have provided valuable insight into the brain mechanisms that mediate the construction of defensive modes with varying degrees of threat imminence. In this Review, we discuss accumulating evidence that the central nucleus of the amygdala (CeA) plays a key role in this process. Specifically, we propose that the mutually inhibitory circuits of the CeA use a winner-takes-all strategy that supports transitioning across defensive modes and the execution of specific defensive behaviors to previously formed threat associations. Our proposal provides a conceptual framework in which seemingly divergent observations regarding CeA function can be interpreted and identifies various areas of priority for future research.