创伤后应激障碍（posttraumatic stress disorder, PTSD）是一类发病率较高的精神疾病。基于消退理论的暴露疗法是临床上PTSD的常用治疗方法，然而PTSD患者消退记忆不能长期维持这一症状限制了暴露疗法的应用。海马作为调节应激和学习记忆的重要脑区，在PTSD形成及恐惧记忆消退中均发挥重要调控作用，内嗅皮层作为海马与皮层间信息传输枢纽，在PTSD中的作用尚不清楚。本课题采用单次延长应激模型，利用化学遗传学、逆向突触示踪、电生理学、分子生物学、免疫组织化学和行为药理学等手段，探索内嗅皮层及其向海马的投射在应激所导致的消退记忆维持损害中的作用，并进一步研究内嗅皮层不同亚区至海马的谷氨酸能和GABA能投射在其中的作用及调控机制。本研究首次从环路水平研究PTSD患者消退记忆不能维持的可能机制，并比较内嗅皮层不同亚区的调控作用，为精神疾病的机制研究和治疗提供新思路和理论依据。

Post-traumatic stress disorder (PTSD) is a high-prevalence psychiatry disorder that occurs after exposure to extremely traumatic experience. Exposure therapy, which is based on the extinction memory, is a widely used treatment for PTSD patients. However, the impairment of fear extinction maintenance results in the difficulty of PTSD treatment. Hippocampus play crucial roles in regulation of stress and memory and entorhinal cortex (EC) has strong, intricate and reciprocal connections with hippocampus and other brain regions. However, the role of EC in PTSD is still unclear. In the present study, using single-prolonged stress (SPS) model, we investigated the roles of the medial and lateral entorhinal cortex (MEC and LEC) in conditioning, extinction and extinction retention of fear memory. We also used DREADD technique.to explore the roles of the glutamatergic or GABAergic projection from LEC or MEC to dorsal or ventral hippocampus, respectively in impairment of extinction memory retention. It is the first study investigating the different roles of lateral and medial regions of EC in animal model of PTSD, providing new target and evidence for studying mechanism of PTSD.