NMDAR-Regulated Dynamics of Layer 4 Neuronal Dendrites during Thalamocortical Reorganization in Neonates
NMDAR-Regulated Dynamics of Layer 4 Neuronal Dendrites during Thalamocortical Reorganization in Neonates
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DOI：
10.1016/j.neuron.2014.02.026
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发表时间：
2014-04-16
期刊：
影响因子：
16.2
通讯作者：
Iwasato, Takuji
中科院分区：
文献类型：
--
作者：
Mizuno, Hidenobu;Luo, Wenshu;Iwasato, Takuji
丘脑皮质(TC)连接在出生后发育过程中由丘脑输入进行重组，然而TC重组的动态特征和潜在的机制仍未被探索。我们以小鼠桶状皮质(Barrel Cell)第四层(L4)星状神经元的树突细化为模型来解决这个问题；L4神经元的树突细化是TC重组的关键组成部分，突触后L4神经元通过它获得面向突触前TC轴突终末的树突方向。同时标记TC轴突和单个桶状细胞树突，可以在体内对新生儿皮质中的树突细化进行时间推移成像。桶状细胞通过动态移动其分支，加强了树突朝向TC轴突的方向。在N-甲基-D-天冬氨酸受体(NMDAR)缺乏的桶状细胞中，这种树突运动增强，定向偏向没有加强。我们的数据表明，在TC重组过程中，L4神经元具有“波动的”树突，NMDARs细胞自主地调节这些动力学来建立微调电路。
Thalamocortical (TC) connectivity is reorganized by thalamic inputs during postnatal development; however, the dynamic characteristics of TC reorganization and the underlying mechanisms remain unexplored. We addressed this question using dendritic refinement of layer 4 (L4) stellate neurons in mouse barrel cortex (barrel cells) as a model; dendritic refinement of L4 neurons is a critical component of TC reorganization through which postsynaptic L4 neurons acquire their dendritic orientation toward presynaptic TC axon termini. Simultaneous labeling of TC axons and individual barrel cell dendrites allowed in vivo time-lapse imaging of dendritic refinement in the neonatal cortex. The barrel cells reinforced the dendritic orientation toward TC axons by dynamically moving their branches. In N-methyl-D-aspartate receptor (NMDAR)-deficient barrel cells, this dendritic motility was enhanced, and the orientation bias was not reinforced. Our data suggest that L4 neurons have "fluctuating'' dendrites during TC reorganization and that NMDARs cell autonomously regulate these dynamics to establish fine-tuned circuits.