Estorgen Effects on Place Cells and Navigation Strategy

该提案探讨了雌激素对空间导航过程中策略使用和海马（HPC）空间表征的影响。雌激素（E）已被发现在动情周期的动情前期和E处理期间引起CA 1锥体细胞的结构变化。因此，假设HPC中的E将导致锥体细胞电生理特性的变化，在高E和低E条件下使空间导航系统偏向于差异策略使用。为了测试这一点，将在整个发情周期的动物内，以及在卵巢切除（OVX）和记录与OVX + E替代动物之间，比较T-迷宫中的自发策略使用。一旦检测到策略使用的差异，将记录HPC CA 1位置细胞，同时大鼠在线索富集环境中在T-迷宫上运行。最初将在OVX和OVX+E动物之间以及随后在动物的动情周期中对位置细胞特性进行比较。为了测试位置细胞的稳定性，位置场的大小和可靠性，以及对加扰和新线索的反应。本研究旨在提供新的信息，行为学习和记忆相关的有据可查的现象，E-诱导的结构变化在HPC，并提供初步数据，E如何影响空间的HPC神经表征。这项研究具有临床意义的记忆和认知的变化与绝经后和老年妇女的E损失的研究。

This proposal examines estrogen effects on strategy use during spatial navigation and on hippocampal (HPC) representations of space. Estrogen (E) has been found to cause structural changes in CA1 pyramidal cells during the proestrus phase of the estrous cycle and during E treatment. Therefore, it is hypothesized that E in the HPC will result in changes in pyramidal cell electrophysiological properties, biasing the spatial navigation system for differential strategy use during high and low E conditions. To test this, spontaneous strategy use in a T-maze will be compared within animals across the estrous cycle, and between ovariectomized (OVX) and recorded and OVX with E replacement animals. Once differences in strategy use are detected, HPC CA1 place cells will be recorded while rats run on T-maze in a cue-enriched environment. Comparisons of place cell properties will initially be made between OVX and OVX+E animals and subsequently across an animal's estrous cycle. To test the stability of place cells, place field size and reliability, and responses to scrambled and novel cues are expected. This study seeks to contribute novel information on behavioral learning and memory correlates of the well-documented phenomenon of E-induced structural changes in HPC, and to provide initial data on how E affects neural representations of space in the HPC. This study has clinical relevance to the study of memory and cognitive changes associated with E loss in post-menopausal and aging women.