Emotional Reaction and Action: From Threat Processing to Goal-Directed Behavior

Abstract

Fear was traditionally studied by using instrumental aversive responses, such as avoidance. This work on instrumental actions failed to lead to a clear understanding of the underlying fear circuitry. Over the past several decades, research on Pavlovian fear reactions has elucidated the circuits that mediate fear. Armed with this information, we return to a consideration of fear-based instrumental actions. While both reactions and actions depend on the amygdala, somewhat different circuits are involved. Fear reactions require connections from the lateral to the central nucleus and from there to the brain stem, while fear-based actions (or at least some such actions) involve connections from the lateral to the basal amygdala and from there to forebrain targets (possibly the striatum). Elucidating the neural mechanisms underlying interactions between Pavlovian and instrumental aversive learning will enhance our understanding of how the brain shifts from passive reactions to actions in the face of danger. This knowledge might aid in understanding how to break the vicious cycle of pathological avoidance in anxiety disorders and could also lead to better coping strategies and other therapeutic interventions.