A distinct entorhinal cortex to hippocampal CA1 direct circuit for olfactory associative learning
A distinct entorhinal cortex to hippocampal CA1 direct circuit for olfactory associative learning
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DOI：
10.1038/nn.4517
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发表时间：
2017-04-01
影响因子：
25
通讯作者：
Zhang, Xiaohui
中科院分区：
文献类型：
--
作者：
Li, Yiding;Xu, Jiamin;Zhang, Xiaohui
内嗅皮层（EC）的外侧和内侧部分分别通过间接EC层2 ->海马齿状回将非空间“什么”和空间“哪里”信息传递到海马CA 1区。CA 3-> CA 1和直接EC层3 -> CA 1路径。然而，它仍然是难以捉摸的直接路径如何传递不同的信息，并有助于海马学习功能。在这里，我们报告，外侧EC投射神经元选择性地形成直接兴奋性突触到一个亚群的形态复杂，钙结合蛋白表达的锥体细胞（PC）在背侧CA 1（dCA 1），而内侧EC神经元均匀支配所有dCA 1 PC。光遗传学失活不同的横向EC-dCA 1连接或突触后dCA 1钙结合蛋白表达PC活动减缓嗅觉联想学习。此外，optetrode记录显示，dCA 1钙结合蛋白表达PC开发更多的选择性尖峰反应的气味线索在学习过程中。因此，我们的研究结果确定了一个直接的横向EC。dCA 1回路，这是嗅觉联想学习所必需的。
Lateral and medial parts of entorhinal cortex (EC) convey nonspatial `what' and spatial `where' information, respectively, into hippocampal CA1, via both the indirect EC layer 2 -> hippocampal dentate gyrus.-> CA3 -> CA1 and the direct EC layer 3 -> CA1 paths. However, it remains elusive how the direct path transfers distinct information and contributes to hippocampal learning functions. Here we report that lateral EC projection neurons selectively form direct excitatory synapses onto a subpopulation of morphologically complex, calbindin-expressing pyramidal cells (PCs) in the dorsal CA1 (dCA1), while medial EC neurons uniformly innervate all dCA1 PCs. Optogenetically inactivating the distinct lateral EC-dCA1 connections or the postsynaptic dCA1 calbindin-expressing PC activity slows olfactory associative learning. Moreover, optetrode recordings reveal that dCA1 calbindin-expressing PCs develop more selective spiking responses to odor cues during learning. Thus, our results identify a direct lateral EC. dCA1 circuit that is required for olfactory associative learning.