CREST, JST, Toyonaka, Osaka 560-0082, Japan.
Nature. 2009 Nov 12;462(7270):218-21. doi: 10.1038/nature08485.
Experience-dependent plasticity in the brain requires balanced excitation-inhibition. How individual circuit elements contribute to plasticity outcome in complex neocortical networks remains unknown. Here we report an intracellular analysis of ocular dominance plasticity-the loss of acuity and cortical responsiveness for an eye deprived of vision in early life. Unlike the typical progressive loss of pyramidal-cell bias, direct recording from fast-spiking cells in vivo reveals a counterintuitive initial shift towards the occluded eye followed by a late preference for the open eye, consistent with a spike-timing-dependent plasticity rule for these inhibitory neurons. Intracellular pharmacology confirms a dynamic switch of GABA (gamma-aminobutyric acid) impact to pyramidal cells following deprivation in juvenile mice only. Together these results suggest that the bidirectional recruitment of an initially binocular GABA circuit may contribute to experience-dependent plasticity in the developing visual cortex.
大脑中的经验依赖性可塑性需要平衡的兴奋-抑制作用。个体回路元件如何影响复杂新皮层网络中的可塑性结果尚不清楚。本文报告了对眼优势可塑性的细胞内分析，即早期剥夺视觉的眼睛的敏锐度和皮质反应性丧失。与典型的锥体神经元偏向逐渐丧失不同，活体中快速放电细胞的直接记录显示出一种反直觉的初始偏向于被剥夺的眼睛，然后是晚期偏向于开放的眼睛，这与这些抑制性神经元的基于尖峰时间的可塑性规则一致。细胞内药理学证实，只有在幼年小鼠中，剥夺后 GABA（γ-氨基丁酸）对锥体细胞的影响才会发生动态转变。这些结果表明，最初的双眼 GABA 回路的双向募集可能有助于发育中的视觉皮层的经验依赖性可塑性。
