Kanold Patrick O, Shatz Carla J
Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
Neuron. 2006 Sep 7;51(5):627-38. doi: 10.1016/j.neuron.2006.07.008.
Synaptic plasticity during critical periods of development requires intact inhibitory circuitry. We report that subplate neurons are needed both for maturation of inhibition and for the proper sign of ocular dominance (OD) plasticity. Removal of subplate neurons prevents the developmental upregulation of genes involved in mature, fast GABAergic transmission in cortical layer 4, including GABA receptor subunits and KCC2, and thus prevents the switch to a hyperpolarizing effect of GABA. To understand the implications of these changes, a realistic circuit model was formulated. Simulations predicted that without subplate neurons, monocular deprivation (MD) paradoxically favors LGN axons representing the deprived (less active) eye, exactly what was then observed experimentally. Simulations also account for published results showing that OD plasticity requires mature inhibition. Thus, subplate neurons regulate molecular machinery required to establish an adult balance of excitation and inhibition in layer 4, and thereby influence the outcome of OD plasticity.
发育关键期的突触可塑性需要完整的抑制性神经回路。我们报告称，皮层下板层神经元对于抑制作用的成熟以及眼优势（OD）可塑性的正确方向均是必需的。去除皮层下板层神经元会阻止参与皮层第4层成熟、快速GABA能传递的基因的发育上调，包括GABA受体亚基和KCC2，从而阻止GABA向超极化效应的转变。为了理解这些变化的影响，构建了一个真实的神经回路模型。模拟预测，没有皮层下板层神经元时，单眼剥夺（MD）反而有利于代表被剥夺（活动较少）眼的外侧膝状体轴突，这正是当时实验所观察到的。模拟结果也解释了已发表的结果，即OD可塑性需要成熟的抑制作用。因此，皮层下板层神经元调节在第4层建立成人兴奋与抑制平衡所需的分子机制，从而影响OD可塑性的结果。
