Abbas Vafaei - Research Center of Physiology, Semnan University of Medical Sciences, Iran, Department of Physiology, Faculty of Medicine, Semnan University of Medical Sciences, Iran
Ali Rashidy-Pour - Research Center of Physiology, Semnan University of Medical Sciences, Iran
Samira Omoumi - Research Center of Physiology, Semnan University of Medical Sciences, Iran
Masoumeh Dadkhah - Research Center of Physiology, Semnan University of Medical Sciences, Iran
Shahla Nourizad - Research Center of Physiology, Semnan University of Medical Sciences, Iran

Background and Aim : Fear extinction is induced when the conditioned stimulus is repeatedly presented without the aversive outcome unconditioned stimulus, resulting in a decline of conditioned fear response. In rodents, fear responses are typically assessed via freezing behavior or the fear-potentiated startle reflex.Methods : Also recent studies revealed that stress and its related hormones modulate the extinction of various memories, including of spatial and auditory fear conditioning. It has been showed that brain glucocorticoid receptors (GRs) are involved in many processes such as fear extinction that drive learning and memory.Results : In this review, we discuss the role of medial prefrontal cortex and its glucocorticoids receptors on fear memory extinction. Also we review some behavioral, pharmacological and neurochemical studies from our laboratory on rodents, which might contribute to our understanding of the complex processes of memory extinction. More importantly, we discuss the pre-reactivation (memory extinction) effects of systemic as well as intra-infralimbic of medial prefrontal cortex infusions of agonist and antagonist of GRs on fear memory extinction.Conclusion : Our findings indicate that medial prefrontal cortex and its glucocorticoid receptors have important role on modulate of fear memory extinction in the rodents.

Glucocorticoid receptors, Fear memory extinction, Medial prefrontal cortex, Rodents