Axonal synapse sorting in medial entorhinal cortex
Axonal synapse sorting in medial entorhinal cortex
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DOI：
10.1038/nature24005
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发表时间：
2017-09-28
期刊：
影响因子：
64.8
通讯作者：
Helmstaedter, Moritz
中科院分区：
文献类型：
--
作者：
Schmidt, Helene;Gour, Anjali;Helmstaedter, Moritz
关于大脑皮层神经元连通性的研究主要集中在神经元之间突触的存在和强度，以及突触后神经元的细胞体和树突上的位置。然而，单个突触前轴突树的突触结构在很大程度上仍然未知。本研究采用三维电子显微镜密集重建的方法研究了大鼠内侧内嗅皮层第2层局部突触前轴突的突触组织，这是网格状空间表征的部位。我们观察到路径长度依赖的轴突突触分选，这样兴奋性神经元的轴突顺序靶向抑制性神经元，然后是兴奋性神经元。连通性分析显示，细胞前馈抑制回路涉及广泛的、有髓鞘的抑制轴突和树突突触聚集。模拟表明，这种高精度电路可以控制内侧内嗅皮层同步活动的传播，这是众所周知的时间精确放电。
Research on neuronal connectivity in the cerebral cortex has focused on the existence and strength of synapses between neurons, and their location on the cell bodies and dendrites of postsynaptic neurons. The synaptic architecture of individual presynaptic axonal trees, however, remains largely unknown. Here we used dense reconstructions from three-dimensional electron microscopy in rats to study the synaptic organization of local presynaptic axons in layer 2 of the medial entorhinal cortex, the site of grid-like spatial representations. We observe path-length-dependent axonal synapse sorting, such that axons of excitatory neurons sequentially target inhibitory neurons followed by excitatory neurons. Connectivity analysis revealed a cellular feedforward inhibition circuit involving wide, myelinated inhibitory axons and dendritic synapse clustering. Simulations show that this high-precision circuit can control the propagation of synchronized activity in the medial entorhinal cortex, which is known for temporally precise discharges.