Imaging excitatory synaptic input to hippocampal dendritic segments during spatial navigation

空间导航过程中海马树突段兴奋性突触输入的成像 Heydar Davoudi，西北大学神经生物学系 项目总结/摘要 海马在空间导航和情景记忆的形成中起着关键作用。海马 输出区CA 1对空间学习和记忆至关重要，它接收来自 内嗅皮层（EC）通过穿孔通路（PP）和海马区CA 2和CA 3通过 Schaffer侧枝（SC）通路。在探索过程中，啮齿动物的CA 1神经元表现出位置特异性活动 称为这些“位置单元”的位置字段。CA 1位置字段可由PP和SC输入路径驱动 到达CA 1树突棘。然而，这两种途径在其中发挥的不同作用尚不清楚。 驱动空间学习和记忆所必需的CA 1位置细胞活动。在这里，我建议制定一个 以前无法实现的CA 1定位细胞索马的同时双色双光子功能成像， 它的突触规模兴奋性输入在头部固定的小鼠导航通过虚拟现实环境。我的目标是 开发基于微棱镜和基于贝塞尔光束的双光子显微镜来对CA 1定位细胞索马成像， 突触尺度兴奋性输入到其基底和远端簇树突段，其分别接收 来自SC和PP途径的输入。这让我可以确定不同的兴奋性突触输入 这两条通路所携带的差异有助于在熟悉的轨道和过程中的躯体位置场 学习新的虚拟环境。总而言之，这项建议旨在增加我们对突触的理解- 在神经和精神疾病如阿尔茨海默氏症中， 疾病和精神分裂症。

Imaging excitatory synaptic input to hippocampal dendritic segments during spatial navigation Heydar Davoudi, Department of Neurobiology, Northwestern University Project Summary/Abstract The hippocampus has a critical role in spatial navigation and formation of episodic memories. Hippocampal output area CA1 is crucial for spatial learning and memory and it receives major excitatory inputs from entorhinal cortex (EC) through the Perforant pathway (PP) and from hippocampal areas CA2 and CA3 through the Schaffer collateral (SC) pathways. During exploration, a rodent’s CA1 neurons show location-specific activity known as place fields of these “place cells”. CA1 place fields may be driven by PP and SC input pathways arriving on CA1 dendritic spines. However, it is unknown what different roles these two pathways play in driving the CA1 place cell activity necessary for spatial learning and memory. Here, I propose to develop a previously-unattainable simultaneous dual-color two-photon functional imaging of a CA1 place cell soma and its synaptic-scale excitatory input in head-fixed mice navigating through a virtual-reality environment. I aim to develop microprism-based and Bessel beam-based two-photon microscopies to image a CA1 place cell soma and the synaptic-scale excitatory input to its basal and distal tuft dendritic segments, which respectively receive inputs from SC and PP pathways. This allows me to determine how the different excitatory synaptic inputs carried by these two pathways differentially contribute to somatic place fields in a familiar track and during learning a new virtual environment. Altogether, this proposal aims to add to our understanding of synaptic- level cognitive processing which is disrupted in neurological and psychiatric diseases such as Alzheimer’s disease and schizophrenia.