Fan cells in lateral entorhinal cortex directly influence medial entorhinal cortex through synaptic connections in layer 1.
Fan cells in lateral entorhinal cortex directly influence medial entorhinal cortex through synaptic connections in layer 1.
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DOI：
10.7554/elife.83008
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发表时间：
2022-12-23
期刊：
影响因子：
7.7
通讯作者：
Nolan MF
中科院分区：
文献类型：
--
作者：
Vandrey B;Armstrong J;Brown CM;Garden DLF;Nolan MF
空间和情景记忆的标准模型表明，外侧内嗅皮层（LEC）和内侧内嗅皮层（MEC）向海马体发送平行的独立输入，每个输入携带不同类型的信息。在这里，我们评估的可能性，信息之间的分工整合的内嗅皮层之前到达海马。我们证明，在小鼠中，扇细胞在LEC的第2层（L2），接受新皮层的输入，并计划到海马齿状回，也发送轴突侧支到MEC的第1层（L1）。扇形细胞输入的激活引起MEC L2中星状细胞和锥体细胞的单突触神经元兴奋，通常随后分别由GABAA和GABAB受体介导的包含快和慢成分的抑制。来自扇细胞的输入也直接激活MEC的L1和L2中的中间神经元，其中来自L1中间神经元的突触连接占L2主细胞群的缓慢前馈抑制。扇细胞激活后兴奋和抑制的相对强度在神经元之间有很大差异，并且在很大程度上与解剖位置无关。我们的研究结果表明，LEC，除了直接影响海马，可以激活或抑制主要的海马输入所产生的MEC。因此，表层MEC中的局部回路可以将联合收割机空间信息与来自LEC的感觉和高阶信号相结合，为整合情景记忆的“什么”和“在哪里”成分提供基底。
Standard models for spatial and episodic memory suggest that the lateral entorhinal cortex (LEC) and medial entorhinal cortex (MEC) send parallel independent inputs to the hippocampus, each carrying different types of information. Here, we evaluate the possibility that information is integrated between divisions of the entorhinal cortex prior to reaching the hippocampus. We demonstrate that, in mice, fan cells in layer 2 (L2) of LEC that receive neocortical inputs, and that project to the hippocampal dentate gyrus, also send axon collaterals to layer 1 (L1) of the MEC. Activation of inputs from fan cells evokes monosynaptic glutamatergic excitation of stellate and pyramidal cells in L2 of the MEC, typically followed by inhibition that contains fast and slow components mediated by GABAA and GABAB receptors, respectively. Inputs from fan cells also directly activate interneurons in L1 and L2 of MEC, with synaptic connections from L1 interneurons accounting for slow feedforward inhibition of L2 principal cell populations. The relative strength of excitation and inhibition following fan cell activation differs substantially between neurons and is largely independent of anatomical location. Our results demonstrate that the LEC, in addition to directly influencing the hippocampus, can activate or inhibit major hippocampal inputs arising from the MEC. Thus, local circuits in the superficial MEC may combine spatial information with sensory and higher order signals from the LEC, providing a substrate for integration of ‘what’ and ‘where’ components of episodic memories.