记忆功能障碍，常伴随脑病，严重时不仅降低生活质量，还会给家庭和社会造成负担。因此研究记忆的编码原理，找出功能障碍的原因，显得尤为重要。齿状回的模式分离被认为是海马神经环路形成不同情景记忆的关键，可是我们对齿状回信息编码的细节及其对整个海马记忆功能的贡献，了解有限。研究表明，齿状回的内侧带和外侧带的神经网络连接不尽相同，预示其功能可能各有侧重。目前，关于外侧带的具体功能，及其与内侧带功能的区别与联系，还未有文献报道。我们的前期实验发现：外侧带颗粒细胞的放电模式也具有空间特异性，同时也能区分不同的过往经历。本项目拟在此基础上，继续采用活体电生理技术和行为学方法，系统地比较内外侧带在情景记忆形成过程中，神经网络放电模式的异同，了解其编码原理。同时，我们拟用药物分别损毁内外侧带，观察下游CA3和CA1神经活动的变化，进一步阐明齿状回在情景记忆编码中的作用，为记忆相关疾病的病因及其治疗提供新思路。

Patients with server memory deficits, which usually caused by brain diseases, suffer from poor quality of life and massive health care costs. Thus it is particularly important to understand the principle of memory formation and possible causes of memory loss. Pattern separation in the dentate gyrus is considered to be the key mechanism of the hippocampal network to create distinct episodic memories, yet our knowledge about the coding scheme within the dentate gyrus and how it contributes to memory function in the entire hippocampal formation, is quite limited. It has been shown that the enclosed and exposed blades of the dentate gyrus bear non-overlapping neural connectivities, which may lead to functional separations during memory coding. So far, neither the function of the exposed blade, nor the functional relationship between the two blades, has been systematically studied. Our preliminary data showed that the granule cells in the exposed blade had strong spatial tuning, and in addition, they were also sensitive to changes between experiences. We expect to explore the similarities and differences in activity patterns between the two blades during the process of episodic memory coding, and how each individual blade influences memory function of downstream CA3 and CA1 in the hippocampus, by combining in vivo electrophysiology, animal behavior and pharmacological methods. This study will provide a new insight about how episodic memory is formed in the hippocampal circuit and potentially shed light on mechanisms and treatments of memory related diseases.