Major effects of sensory experiences on the neocortical inhibitory circuits
Major effects of sensory experiences on the neocortical inhibitory circuits
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DOI：
10.1523/jneurosci.2478-06.2006
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发表时间：
2006-08-23
影响因子：
5.3
通讯作者：
Sun, Qian-Quan
中科院分区：
文献类型：
--
作者：
Jiao, Yuanyuan;Zhang, Chunzhao;Sun, Qian-Quan
在出生后的发育过程中，感觉经验在皮层连接的完善中起着关键作用。然而，无论是出生后的经验依赖性成熟的新皮层抑制网络的过程及其潜在的机制仍然是难以捉摸的。在这里，我们研究了皮层内抑制网络的第四层中的“感觉-备用”和“感觉-剥夺”皮层的谷氨酸脱羧酶67（GAD 67）-绿色荧光蛋白（GFP）（三角洲新）和野生型小鼠的差异特性。我们的研究结果表明，行D晶须修剪（WT）开始于出生后第7天（P7），但不是在P15后，诱导小白蛋白（PV）的表达，测定PV/GFP的比率和PV细胞密度，在剥夺桶的强劲下降。WT还诱导了一个强大的减少抑制性体周静脉曲张和突触GAD 65/67免疫反应的剥夺桶的多刺神经元的数量。虽然GAD 65/67在中间神经元中的表达也在剥夺桶中下调，但GFP表达保持不变。膜片钳记录从多刺细胞显示了1.5倍减少皮质内诱发的IPSC（eIPSC）在剥夺与备用皮质。eIPSC的减少通过突触前特性和单一IPSC振幅的变化发生。微型IPSC在两种实验条件下表现出微妙但显著的差异。此外，在剥夺桶中的IPSC的性质类似于在未成熟脑中记录的IPSC的性质（P7）。总之，这些结果表明，局部皮质内抑制网络的属性被感官体验修改。PV阳性篮状细胞介导的体周抑制通过感觉剥夺被修剪。
During postnatal development, sensory experiences play critical roles in the refinement of cortical connections. However, both the process of postnatal experience-dependent maturation of neocortical inhibitory networks and its underlying mechanisms remain elusive. Here, we examined the differential properties of intracortical inhibitory networks of layer IV in "sensory-spared" and "sensory-deprived" cortices of glutamate acid decarboxylase 67 (GAD67)-green fluorescent protein (GFP) (Delta neo) and wild-type mouse. Our results showed that row D whisker trimming (WT) begun at postnatal day 7 (P7), but not after P15, induced a robust reduction of parvalbumin (PV) expression, measured by the PV/GFP ratio and PV cell densities, in the deprived barrels. WT also induced a robust reduction in the number of inhibitory perisomatic varicosities and synaptic GAD65/67 immunoreactivities in spiny neurons of the deprived barrels. Although the GAD65/67 expressions in interneurons were also downregulated in the deprived barrels, the GFP expression remained unchanged. Patch-clamp recording from spiny cells showed a 1.5-fold reduction of intracortical evoked IPSCs (eIPSCs) in deprived versus spared cortices. The reduction in eIPSCs occurred via changes in presynaptic properties and unitary IPSC amplitudes. Miniature IPSCs showed subtle but significant differences between the two experimental conditions. In addition, properties of the IPSCs in deprived barrels resemble those of IPSCs recorded in immature brains (P7). Together, these results suggest that the properties of local intracortical inhibitory networks are modified by sensory experiences. Perisomatic inhibition mediated by PV-positive basket cells is pruned by sensory deprivation.