SYNAPTIC ORGANIZATION OF RETROHIPPOCAMPAL PATHWAYS

本研究的目的是研究海马神经元的突触组织。 成年大鼠丘下复合体的传出和内在投射。 脑内各亚区突触组织的差异 小叶复合体(原小叶、固有小叶、小叶前和 将对小丘旁)进行研究，以确定生理差异 与这些亚区显著的细胞学差异有关。 跨学科的神经生理学，细胞内HRP追踪，以及 免疫细胞化学技术将一起使用，并将提供 任何一种技术都无法单独提供的信息。传出 从下复合体到内嗅皮层的投射和 我们将检查杏仁核，以及这些区域的固有回路。 这些途径将通过细胞内记录来研究；细胞内 注射HRP以识别神经元并追踪其轴突投射； 和谷氨酸脱羧酶(GAD)免疫细胞化学定位 候选抑制性中间神经元的体细胞和突触终末 它们与主神经元的关系。建议的研究将会(1) 丘脑下传出轴突内嗅觉靶点和杏仁核靶点的建立 以及下丘脑传出神经在这些靶点上的生理作用，(2) 提供有关轴突程度差异的定量信息 分支到不同子区域内的单元的目标区域 亚细胞复合体(使用细胞内示踪技术)，(3) 指示传出细胞的定位和生理特性 在下复合体的特定亚区内，以及(4)阐明 主神经元之间的突触关系与GABA能抑制 中间神经元。这些研究将填补我们知识上的重大空白 关于下丘复合体的突触组织，这种结构 现在被广泛认为是海马体结构的主要来源 传出物。

The objective of this research is to study the synaptic organization of efferent and intrinsic projections of the subicular complex in adult rats. Differences of synaptic organization within the sub-regions of the subicular complex (prosubiculum, subiculum proper, presubiculum, and parasubiculum) will be studied in order to define physiological differences related to the marked cytological differences in these sub-regions. Interdisciplinary neurophysiological, intracellular HRP tracing, and immunocytochemical techniques will be used together, and will provide information that none of the techniques could provide alone. The efferent projections from the subicular complex to the entorhinal cortex and amygdala will be examined, as well as circuitry intrinsic to these areas. The pathways will be studied by intracellular recording; intracellular injection of HRP to identify neurons and trace their axonal projections; and glutamic acid decarboxylase (GAD) immunocytochemistry to localize the somata and synaptic terminals of candidate inhibitory interneurons and their relationship to principal neurons. The proposed studies will (1) establish the entorhinal and amygdala targets of subicular efferent axons and the physiological action of subicular efferents on these targets, (2) provide quantitative information about differences in the degree of axonal branching to target areas of cells within different sub-regions of the subicular complex (by the use of intracellular tracing techniques), (3) indicate the localization and physiological properties of efferent cells within specific sub-regions of the subicular complex, and (4) clarify the synaptic relationship between principal neurons and GABAergic inhibitory interneurons. These studies will fill significant gaps in our knowledge about the synaptic organization of the subicular complex, a structure that is now widely recognized as the major source of hippocampal formation efferents.