PFC-MTL FUNCTIONAL INTERACTIONS IN SPATIAL MEMORY

本研究将情境引导联想记忆中PFC-MTL相互作用的中心模型扩展到大鼠空间导航领域。在其他项目中，我们将测试的假设，即PFC开发的背景下抽象出更具体的MTL代码的一般化表示， 海马神经元编码的关联依赖于特定的PFC回路。这个项目将采用一个测试协议来评估上下文引导的记忆，这是正式相同的其他项目。然而，在这里，我们将研究上下文引导的学习和空间路径的选择，从而将空间导航和路径整合的MTL机制与PFC机制联系起来 支持抽象规则学习和奖励期望。该项目的设计与项目4密切对应，项目4使用上下文线索来指导对象奖励关联，这种密切的对应关系将使我们能够直接比较空间和非空间上下文指导关联的机制。的 特定的目标联合收割机结合高密度记录和暂时失活的目标PFC和MTL地区的行为大鼠，以确定功能和生理编码的贡献对相互作用的额叶和颞叶网络。在每个目标中，大鼠将被训练根据环境背景选择不同的路线。目标1将分析多个单个单元和局部场电位（LFP）， 放置在PFC和MTL靶中的四极管束。目的2将使用双侧或交叉同侧相同脑区的暂时失活来研究它们在上下文选择路径中的因果作用。 目标3将探讨如何编码功能在一个区域依赖于其他结合局部回路失活和记录。结果将有助于解释项目1-4中描述的人类和猴子的脑损伤和活动机制。分析核心将比较项目3-5的数据，以量化不同物种和不同类型的上下文环境中神经编码的相似性和差异。 协会，该项目将有助于约束和指导项目6中的计算建模。

This project extends the Center model of PFC-MTL interactions in context-guided associative memory to the domain of spatial navigation in rats. As in the other projects, we will test the hypothesis that the PFC develops generalized representations of context abstracted from more specific MTL codes, and that context dependent associations coded by hippocampal neurons depend upon specific PFC circuits. This project will employ a testing protocol to assess context guided memory that is formally identical to those of other projects. However, here we will investigate context-guided learning and selection of spatial routes, thereby linking well investigated MTL mechanisms of spatial navigation and path integration with PFC mechanisms that support abstract rule learning and reward expectancies. The project design corresponds closely with Project 4, which uses contextual cues to guide object reward associations, and this close correspondence will allow us to directly compare mechanisms of spatial and nonspatial context-guided associations. The specific aims combine high density recording and temporary inactivation in targeted PFC and MTL regions in behaving rats to determine the functional and physiological coding contributions of pairs of interacting frontal and temporal networks. In each aim, rats will be trained to select different routes depending on the environmental context. Aim 1 will analyze multiple single units and local field potentials (LFP) in pairs of tetrode bundles placed in PFC and MTL targets. Aim 2 will use either bilateral or crossed ipsilateral temporary inactivation of the same brain regions to investigate their causal role in context selective routes. Aim 3 will explore how coding features in one region depend upon the other by combining local circuit inactivation and recording. Results will help interpret the mechanisms of brain impairment and activity described in humans and monkeys in Projects 1-4. The Analytic Core will compare the data from Projects 3-5 to quantify the similarities and differences in neural coding across species and types of contextual associations, and the project will help constrain and be guided by the computational modeling in Project 6.