Neurobiology of Fear Memory

The neural circuitry of fear is complex, as a multitude of brain regions and networks orchestrate various aspects of fear including acquisition, expression, and extinction. The primary brain areas involved in fear include the amygdala, medial prefrontal cortex, hippocampus, and periaqueductal gray, each of which is comprised of a heterogeneous neuronal population. Interplay within and between these brain regions allows behaviors observed in fear learning to proceed, including spatial processing and Pavlovian associations of a cue with an aversive footshock. Understanding the circuits underlying these fear behaviors is critical not only to gain a better knowledge about associative learning, but also to delineate underlying mechanisms of fear-related disorders including posttraumatic stress disorder. This chapter attempts to provide a synthesis of the neural circuits underlying Pavlovian fear conditioning and various aspects of fear.