Developmental Synaptic Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
Nat Neurosci. 2010 Oct;13(10):1240-8. doi: 10.1038/nn.2639.
Feedforward GABAergic inhibition sets the dendritic integration window, thereby controlling timing and output in cortical circuits. However, the manner in which feedforward inhibitory circuits emerge is unclear, despite this being a critical step for neocortical development and function. We found that sensory experience drove plasticity of the feedforward inhibitory circuit in mouse layer 4 somatosensory barrel cortex in the second postnatal week via two distinct mechanisms. First, sensory experience selectively strengthened thalamocortical-to-feedforward interneuron inputs via a presynaptic mechanism but did not regulate other inhibitory circuit components. Second, experience drove a postsynaptic mechanism in which a downregulation of a prominent thalamocortical NMDA excitatory postsynaptic potential in stellate cells regulated the final expression of functional feedforward inhibitory input. Thus, experience is required for specific, coordinated changes at thalamocortical synapses onto both inhibitory and excitatory neurons, producing a circuit plasticity that results in maturation of functional feedforward inhibition in layer 4.
前馈 GABA 能抑制设定了树突整合窗口，从而控制皮质回路中的时间和输出。然而，尽管这是新皮层发育和功能的关键步骤，但前馈抑制回路出现的方式尚不清楚。我们发现，在出生后第二周，感觉经验通过两种不同的机制驱动了小鼠体感皮层 4 层前馈抑制回路的可塑性。首先，感觉经验通过一种突触前机制选择性增强了丘脑皮质到前馈中间神经元的输入，但不调节其他抑制性回路成分。其次，经验驱动了一种突触后机制，其中星状细胞中明显的丘脑皮质 NMDA 兴奋性突触后电位的下调调节了功能性前馈抑制输入的最终表达。因此，经验对于在抑制性和兴奋性神经元上的丘脑皮质突触的特定、协调的变化是必需的，产生导致功能前馈抑制在 4 层成熟的回路可塑性。
