Neural circuits for a top-down control of fear and extinction.

Fear learning and extinction are controlled by the activity of three interconnected regions: the amygdala, hippocampus, and prefrontal cortex. Of these, the medial prefrontal cortex modulates specific aspects in fear and extinction via a top-down regulation. In recent years, extensive progress has been made in our understanding of the neural circuits that mediate fear-related behaviors and their modulation by ascending systems. The development of new experimental techniques is now revealing the details of the intrinsic circuits within these structures as well as the connections between them. Here, we highlight recent advances in our understanding of how the prefrontal cortex may mediate such a top-down regulation.