Abstract:

Exposure therapy is a type of cognitive behavioral therapy used for treatment of post-traumatic stress disorder. Using the cognitive behavioral therapy, the fear memory can be extinguished if the subjects are repeatedly exposed to a conditioned stimulus in absence of an unconditioned stimulus. However, the fear memory is not completely erased and tends to relapse in some conditions. Fear renewal is a typical model of fear relapse, which is induced when subjects are exposed to contexts outside of the extinction training. The hippocampus, medial prefrontal cortex and amygdala are critical brain regions involved in fear renewal and the connections and circuitries between these brain areas are also crucial physiological bases for fear renewal. The hippocampus regulates the amygdala activity by its direct projection to the basal amygdala or by its indirect projection via the prelimbic cortex in the renewal.

Key words: fear memory, neural circuit, renewal, context, extinction