Abstract

The entorhinal cortex (EC) is a brain region that has been shown to be essential for memory functions and spatial navigation. However, detailed three-dimensional (3D) synaptic morphology analysis and identification of postsynaptic targets at the ultrastructural level have not been performed before in the human EC. In the present study, we used Focused Ion Beam/Scanning Electron Microscopy to perform a 3D analysis of the synapses in the neuropil of medial EC in layers II and III from human brain autopsies. Specifically, we studied synaptic structural parameters of 3561 synapses, which were fully reconstructed in 3D. We analyzed the synaptic density, 3D spatial distribution, and type (excitatory and inhibitory), as well as the shape and size of each synaptic junction. Moreover, the postsynaptic targets of synapses could be clearly determined. The present work constitutes a detailed description of the synaptic organization of the human EC, which is a necessary step to better understand the functional organization of this region in both health and disease.

中文翻译：

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人类内嗅皮层突触的 3D 超微结构研究。

摘要

内嗅皮层 (EC) 是一个大脑区域，已被证明对记忆功能和空间导航至关重要。然而，之前在人类 EC 中尚未进行详细的三维 (3D) 突触形态分析和超微结构水平的突触后靶标识别。在本研究中，我们使用聚焦离子束/扫描电子显微镜对来自人脑尸检的 II 层和 III 层内侧 EC 神经细胞中的突触进行 3D 分析。具体来说，我们研究了 3561 个突触的突触结构参数，这些突触在 3D 中完全重建。我们分析了突触密度、3D 空间分布和类型（兴奋性和抑制性），以及每个突触连接的形状和大小。此外，可以清楚地确定突触的突触后目标。