Strengthening of lateral activation in adult rat visual cortex after retinal lesions captured with voltage-sensitive dye imaging in vivo
Strengthening of lateral activation in adult rat visual cortex after retinal lesions captured with voltage-sensitive dye imaging in vivo
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DOI：
10.1073/pnas.0900068106
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发表时间：
2009-05
期刊：
影响因子：
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通讯作者：
Ganna Palagina;U. Eysel;D. Jancke
中科院分区：
文献类型：
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作者：
Ganna Palagina;U. Eysel;D. Jancke
外周损伤引起的感觉剥夺可在最初沉默的皮质区域引发功能性皮质重组。有人认为，皮质内的连通性能够在这样的病变投影区(LPZ)内恢复功能，从而取代失去的皮质下输入。在这里，我们研究了视网膜损伤引起的成年大鼠初级视皮层侧连接功能的变化。使用电压敏感的染料记录，我们以毫秒级的分辨率可视化了突触活动在LPZ上的传播。损伤后不久，LPZ内的大多数神经元被来自未受影响的皮质区域的活动的延迟传播激活。随着恢复时间的延长，LPZ内的潜伏期逐渐减少，激活达到阈值以上水平。靶向电极记录证实，LPZ内神经元的感受场移位到视网膜病变边缘，同时显示出正常的方向和方向选择性。这些结果证实了皮层水平连接在功能重组中起中心作用的观点，如图所示，突触活动的逐渐促进和水平传播到被剥夺的皮质区域的兴奋行波所揭示的那样。
Sensory deprivation caused by peripheral injury can trigger functional cortical reorganization across the initially silenced cortical area. It is proposed that intracortical connectivity enables recovery of function within such a lesion projection zone (LPZ), thus substituting lost subcortical input. Here, we investigated retinal lesion-induced changes in the function of lateral connections in the primary visual cortex of the adult rat. Using voltage-sensitive dye recordings, we visualized in millisecond-time resolution spreading synaptic activity across the LPZ. Shortly after lesion, the majority of neurons within the LPZ were subthresholdly activated by delayed propagation of activity that originated from unaffected cortical regions. With longer recovery time, latencies within the LPZ gradually decreased, and activation reached suprathreshold levels. Targeted electrode recordings confirmed that receptive fields of intra-LPZ neurons were displaced to the retinal lesion border while displaying normal orientation and direction selectivity. These results corroborate the view that cortical horizontal connections have a central role in functional reorganization, as revealed here by progressive facilitation of synaptic activity and the traveling wave of excitation that propagates horizontally into the deprived cortical region.