Flee or Freeze: The Differential Role of Amygdala Subregions in Fear and Avoidance

Abstract

Fear is a powerful emotion that is crucial to the survival in a complex environment. The amygdala, a key brain region implicated in processing fear, is not homogenous but comprises of several subregions, most notably the central amygdala (CEA) and the basolateral amygdala (BLA). To examine their functional differences, this study utilized a novel naturalistic approach-food avoid predator task and a standard classical fear conditioning task to examine defensive responses in CEA and BLA lesioned rats. Both lesioned groups demonstrated impaired fear responses than sham; however, BLA lesioned animals showed more impairments in active defensive responses (i.e., fleeing), while CEA lesioned animals showed more impairments in passive defensive responses (i.e., freezing). Maladaptation of fear can lead to serious mental illnesses; these findings may elucidate how fear is processed and facilitate the discovery of more effective treatment of disorders such as such as post-traumatic stress disorder (PTSD).