DISYNAPTIC INHIBITION OF SPINAL MOTONEURONS FROM MOTOR CORTEX IN MONKEY
DISYNAPTIC INHIBITION OF SPINAL MOTONEURONS FROM MOTOR CORTEX IN MONKEY
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DOI：
10.1113/jphysiol.1976.sp011431
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发表时间：
1976-01-01
影响因子：
5.5
通讯作者：
TANAKA, R
中科院分区：
文献类型：
--
作者：
JANKOWSKA, E;PADEL, Y;TANAKA, R
本文研究了猕猴病毒皮质脊髓束对脊髓运动神经元的双突触抑制机制。使用表面刺激或皮质内弱刺激来唤起抑制作用。细胞内记录来自腰椎节段的运动神经元。运动轴突对拮抗肌的条件性刺激抑制了由Ia组传入诱发的双突触IPSP和由皮质脊髓纤维诱发的双突触IPSP。当神经冲动同时到达被探测的脊髓节段时，这两个纤维系统的活动就相互促进了。来自Ia组传入和运动皮质的双突触IPSP可能是由共同的中间神经元介导的。通过比较不同运动核团诱发单突触E[兴奋性]PSP和双突触IPSP的皮质面积，没有证据表明相同的锥体束细胞投射到1个运动核的运动神经元和介于Ia组传入和拮抗肌肉运动神经元之间的中间神经元。在单个运动神经元中诱发双突触IPSP的区域在大小上与皮质单突触投射到运动神经元的区域相似，并显示出相似的重叠程度，表明锥体束细胞向Ia抑制中间神经元的投射与向运动神经元的投射一样广泛，而且它们的组织结构相似。
The neuronal mechanism of disynaptic inhibition of spinal motoneurons by the corticospinal tract was investigated in Macaca irus. Surface stimulation or weak intracortical stimulation was used in order to evoke the inhibition. Intracellular records were taken from motoneurons in lumbar segments. Both the disynaptic IPSP [inhibitory postsynaptic potential] evoked from group Ia afferents and the disynaptic IPSP evoked from corticospinal fibers were depressed by conditioning stimulation of motor axons to antagonistic muscles. Mutual facilitation of the actions from these 2 fiber systems occurred when nerve impulses set up in them reached the explored spinal segment synchronously. Disynaptic IPSP from group Ia afferents and from the motor cortex may be mediated by common interneurons. No evidence either for or against projections of the same pyramidal tract cells to motoneurons of 1 motor nucleus and to interneurons interposed between group Ia afferents and motoneurons of an antagonistic muscle could be obtained by comparing cortical areas from which monosynaptic E[excitatory]PSP and disynaptic IPSP were evoked in different motor nuclei. The areas from which the disynaptic IPSP were evoked in individual motoneurons appeared to be similar in size to the areas of cortical monosynaptic projections to motoneurons and showed similar degrees of overlap, indicating that the projections of pyramidal tract cells to Ia inhibitory interneurons are as extensive as to motoneurons and that they are similarly organized.