Gandhi Sunil P, Yanagawa Yuchio, Stryker Michael P
Keck Center for Integrative Neuroscience, Department of Physiology, University of California, San Francisco, CA 94143-0444, USA.
Proc Natl Acad Sci U S A. 2008 Oct 28;105(43):16797-802. doi: 10.1073/pnas.0806159105. Epub 2008 Oct 21.
During postnatal development, altered sensory experience triggers the rapid reorganization of neuronal responses and connections in sensory neocortex. This experience-dependent plasticity is disrupted by reductions of intracortical inhibition. Little is known about how the responses of inhibitory cells themselves change during plasticity. We investigated the time course of inhibitory cell plasticity in mouse primary visual cortex by using functional two-photon microscopy with single-cell resolution and genetic identification of cell type. Initially, local inhibitory and excitatory cells had similar binocular visual response properties, both favoring the contralateral eye. After 2 days of monocular visual deprivation, excitatory cell responses shifted to favor the open eye, whereas inhibitory cells continued to respond more strongly to the deprived eye. By 4 days of deprivation, inhibitory cell responses shifted to match the faster changes in their excitatory counterparts. These findings reveal a dramatic delay in inhibitory cell plasticity. A minimal linear model reveals that the delay in inhibitory cell plasticity potently accelerates Hebbian plasticity in neighboring excitatory neurons. These findings offer a network-level explanation as to how inhibition regulates the experience-dependent plasticity of neocortex.
在出生后的发育过程中，改变的感觉体验会触发感觉新皮层中神经元反应和连接的快速重组。这种依赖于经验的可塑性会因皮质内抑制的减少而受到破坏。关于抑制性细胞自身的反应在可塑性过程中如何变化，我们知之甚少。我们通过使用具有单细胞分辨率的功能性双光子显微镜和细胞类型的基因鉴定，研究了小鼠初级视觉皮层中抑制性细胞可塑性的时间进程。最初，局部抑制性和兴奋性细胞具有相似的双眼视觉反应特性，两者都偏向对侧眼。在单眼视觉剥夺2天后，兴奋性细胞反应转向偏向睁开的眼睛，而抑制性细胞对被剥夺的眼睛的反应仍然更强。到剥夺4天时，抑制性细胞反应发生转变，以匹配其兴奋性对应细胞更快的变化。这些发现揭示了抑制性细胞可塑性的显著延迟。一个最小线性模型表明，抑制性细胞可塑性的延迟有力地加速了相邻兴奋性神经元中的赫布可塑性。这些发现为抑制如何调节新皮层的经验依赖性可塑性提供了一个网络层面的解释。
