SYNAPTIC ORGANIZATION OF RETROHIPPOCAMPAL PATHWAYS

本研究的目的是研究突触的组织， 成年大鼠下托复合体的传出和内源性投射。 突触组织的差异内的亚区域的 下托复合体（prosubiculum，subiculum proper，presubiculum，and 将研究以确定生理差异 与这些次区域的显著细胞学差异有关。 跨学科神经生理学，细胞内HRP示踪，和 免疫细胞化学技术将一起使用，并将提供 没有一种技术可以单独提供的信息。 传出 从下托复合体到内嗅皮质的投射， 将检查杏仁核以及这些区域固有的电路。 将通过细胞内记录研究这些途径;细胞内 注射HRP鉴定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胞体和突触末梢， 与主要神经元的关系。 拟议的研究将（1） 建立下托传出轴突的内嗅和杏仁核靶点 以及下托传出神经对这些靶点的生理作用;（2） 提供有关轴突损伤程度差异的定量信息， 分支到细胞的不同子区域内的目标区域， 下托复合体（通过使用细胞内示踪技术），（3） 指示传出细胞的定位和生理特性 在特定的subicular复合体的子区域，（4）澄清， 主神经元与GABA能抑制性神经元突触关系 中间神经元。 这些研究将填补我们知识上的重大空白 关于下托复合体的突触组织， 现在被广泛认为是海马结构的主要来源 传出神经

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.