Chapter 17 The Innate Alarm System A Translational Approach

The innate alarm system responds adaptively to imminent threat. Perceived danger is processed subconsciously, without the need for conscious appraisal of the stimulus, facilitating this rapid response. Here, we review research implementing preclinical, animal models to investigate behavioral defensive responses and to identify the underlying neurocircuitry phylogenetically conserved for survival in mammals and humans. Studies on subconscious processing of threat in healthy humans follow, providing an overview of the neural correlates of innate defense responses when facing imminent threat. Subsequently, we review research on subconscious processing in posttraumatic stress disorder, a disorder often characterized by chronic inescapable stress, and identify aberrant neural functioning related to innate defense mechanisms. Taking into account previous findings, we end the chapter by proposing a neural model for the innate alarm system that encompasses critical cortical and subcortical regions underlying reflexive innate defense reactions when facing imminent threat. Clinical and research implications follow.