Amygdala microcircuits mediating fear expression and extinction.

This review summarizes the latest developments in our understanding of amygdala networks that support classical fear conditioning, the experimental paradigm most commonly used to study learned fear in the laboratory. These recent advances have considerable translational significance as congruent findings from studies of fear learning in animals and humans indicate that anxiety disorders result from abnormalities in the mechanisms that normally regulate conditioned fear. Because of the introduction of new techniques and the continued use of traditional approaches, it is becoming clear that conditioned fear involves much more complex networks than initially believed, including coordinated interactions between multiple excitatory and inhibitory circuits within the amygdala.