Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita, Japan.
Hippocampus. 2019 Apr;29(4):305-312. doi: 10.1002/hipo.23064. Epub 2018 Dec 26.
Recurrent excitatory synapses have theoretically been shown to play roles in memory storage and associative learning and are well described to occur in the CA3 region of the hippocampus. Here, we report that the CA2 region also contains recurrent excitatory monosynaptic couplings. Using dual whole-cell patch-clamp recordings from CA2 pyramidal cells in mouse hippocampal slices under differential interference contrast microscopic controls, we evaluated monosynaptic excitatory connections. Unitary excitatory postsynaptic potentials occurred in 1.4% of 502 cell pairs. These connected pairs were preferentially located in the superficial layer and proximal part (CA2b) of the CA2 region. These results indicate that recurrent excitatory circuits are denser in the CA2 region than in the CA1 region, as well as in the CA3 region.
理论上已经证明，反复兴奋的突触在记忆存储和联想学习中发挥作用，并且在海马体的 CA3 区域中得到了很好的描述。在这里，我们报告 CA2 区域也包含反复兴奋的单突触连接。使用双全细胞膜片钳记录在差异干涉对比显微镜控制下的小鼠海马切片中的 CA2 锥体神经元，我们评估了单突触兴奋性连接。在 502 对细胞中，有 1.4%出现了单位兴奋性突触后电位。这些连接对优先位于 CA2 区域的浅层和近端部分 (CA2b)。这些结果表明，与 CA1 区域以及 CA3 区域相比，CA2 区域的反复兴奋性回路更加密集。
