BEHAVIORAL AND PLACE CORRELATES OF HIPPOCAMPAL NEURONS

该项目的广泛、长期目标是描述 认知功能中海马神经活动的本质 为学习和记忆服务。这一知识将有助于 我们对记忆障碍神经学基础的理解 由于衰老和疾病导致的海马体系统功能障碍。 该项目有两个具体目标：1)澄清 海马区主要放电的基本功能相关研究 执行记忆任务的大鼠的神经元，以及2)描述 这些相关基因在海马区的局部组织 大脑皮层。建议的实验设计采用了 慢性单位记录将棘波活动与感觉和 辨别学习与空间导航中的行为事件 表现依赖于海马体通路的任务。 涉及生理和行为的计算机化分析 将使用措施来发现尖峰的最佳相关性 关键任务事件的活动。我们将特别注意 单位活动可以用两个因素来解释的程度 在先前对海马体单位的描述中突出的参数， “行为”参数，包括学习到的刺激和反应 的意义，而不是“地点”或空间位置 动物。对同一个细胞的放电相关性的比较 跨每个任务内的参数和跨单独的任务将 用来推断高阶函数的公共属性 跨任务变化。基于神经心理学数据，我们的 工作假设是，这些更高阶属性将 反映海马神经元对刺激配置的编码。 具体的实验将集中在1)识别 反映任务事件配置的功能关联，2) 关于这些相关因素在这一过程中的发展 学习，以及3)在断开连接后它们消失 海马区通路。 建议的实验包括从几个单一的- 单元同时使用两种不同类型的多通道 微电极。这些方法不仅会增加 数据收集的效率，但也将允许探索 功能相关的解剖学组织在 海马体。分析将重点放在功能上的比较上 主要海马区之间的相互关系和比较 同时记录的近邻和远邻细胞间的差异。 这些分析将用于生成和确认 关于处理机制的假设反映在 单个神经元的功能关联。

The broad, long-term objective of this project is to describe the nature of hippocampal neural activity in cognitive functions subserving learning and memory. This knowledge will contribute to our understanding of the neurological basis of memory disorders consequent to hippocampal-system dysfunction in aging and disease. There are two specific aims of the project: 1) to clarify the basic functional correlates of firing in hippocampal principal neurons in rats performing memory tasks, and 2) to describe the topographical organization of those correlates in the hippocampal cortex. The proposed experimental design exploits new methods in chronic unit recording to correlate spike activity with sensory and behavioral events in discrimination learning and spatial navigation tasks for which performance is dependent on hippocampal pathways. Computerized analyses involving physiological and behavioral measures will be used to uncover the optimal correlate of spike activity to key task events. Particular attention will be paid to the degree to which unit activity can be explained by two parameters prominent in previous descriptions of hippocampal units, "behavioral" parameters, including stimuli and responses of learned significance, versus "place" or allocentric spatial position of the animal. Comparison of the firing correlates for the same cell both across parameters within each task, and across separate tasks will be used to infer the higher-order functional attributes common across task variations. Based on neuropsychological data, our working hypothesis is that these higher order attributes will reflect encoding of stimulus configurations by hippocampal neurons. Specific experiments will focus 1) on the identification of functional correlates reflecting configurations of task events, 2) on the development of these correlates during the course of learning, and 3) on their disappearance after disconnection of hippocampal pathways. The proposed experiments involve recording from several single- units simultaneously using two different kinds of multichannel microelectrode. These methods will not only increase the efficiency of data collection, but will also permit an exploration of the anatomical organization of functional correlates within the hippocampus. Analyses will focus on comparisons of the functional correlates among the major hippocampal regions and on comparisons among near and distant neighboring cells recorded simultaneously. These analyses will be used both to generate and to confirm hypotheses about the processing mechanisms reflected in the functional correlates of individual neurons.