Physiologisches Institut, Universität Bern, Bühlplatz 5, CH-3012 Bern, Switzerland.
Science. 2012 Feb 24;335(6071):989-93. doi: 10.1126/science.1217276.
Interhemispheric inhibition is thought to mediate cortical rivalry between the two hemispheres through callosal input. The long-lasting form of this inhibition is believed to operate via γ-aminobutyric acid type B (GABA(B)) receptors, but the process is poorly understood at the cellular level. We found that the firing of layer 5 pyramidal neurons in rat somatosensory cortex due to contralateral sensory stimulation was inhibited for hundreds of milliseconds when paired with ipsilateral stimulation. The inhibition acted directly on apical dendrites via layer 1 interneurons but was silent in the absence of pyramidal cell firing, relying on metabotropic inhibition of active dendritic currents recruited during neuronal activity. The results not only reveal the microcircuitry underlying interhemispheric inhibition but also demonstrate the importance of active dendritic properties for cortical output.
两半球间抑制被认为通过胼胝体输入来调节两个半球之间的皮层竞争。这种抑制的持久形式被认为通过γ-氨基丁酸 B 型（GABA(B)）受体起作用，但在细胞水平上这一过程知之甚少。我们发现，当大鼠体感皮层的 5 层锥体神经元因对侧感觉刺激而被激发时，当与同侧刺激配对时，其放电会被抑制数百毫秒。这种抑制通过 1 层中间神经元直接作用于树突顶端，但在没有锥体神经元放电的情况下处于沉默状态，它依赖于在神经元活动期间募集的主动树突电流的代谢型抑制。研究结果不仅揭示了两半球间抑制的微观电路，还证明了主动树突特性对皮质输出的重要性。
