Linear transmission of cortical oscillations to the neural drive to muscles is mediated by common projections to populations of motoneurons in humans
Linear transmission of cortical oscillations to the neural drive to muscles is mediated by common projections to populations of motoneurons in humans
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DOI：
10.1113/jphysiol.2010.202473
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发表时间：
2011-02-01
影响因子：
5.5
通讯作者：
Farina, Dario
中科院分区：
文献类型：
--
作者：
Negro, Francesco;Farina, Dario
非技术概述由于人类中枢神经系统通过对脊髓运动神经元的输入来控制肌肉收缩，因此在随意运动期间在初级运动皮层上记录的振荡与在肌肉表面上产生的电活动相关。我们通过理论推导和实验记录表明，皮质输入部分以线性方式传递到运动神经元的人口。结果表明，有效的传播的皮质投射到运动神经元池，让一个有效的控制肌肉的力量输出。在初级运动皮层的振荡通过皮质脊髓束传递到运动神经元池。这种传输之前已经研究了使用EEG和表面EMG信号的并发记录之间的相干性分析。在这项研究中，我们使用了一个数学推导和运动单位记录在体内调查的起源线性传输的皮质输入到运动神经元的尖峰列车（神经驱动肌肉）。理论推导表明，一个共同的输入传播到一个相对较少的运动神经元的一部分是以线性的方式传输，克服了个别运动神经元的非线性产生的干扰信号。我们进一步计算了7名健康男性的实验EEG信号和小指外展肌运动单位的累积尖峰序列之间的皮质肌相干性。实验结果表明，平均而言，只有四到五个运动单位是足以达到相同的水平的一致性估计从表面肌电图。结果表明，在传输的皮质输入运动神经元通过皮质脊髓束的线性实现，因为（i）这种输入是很大程度上共同的所有运动神经元，和（ii）其频率内容只需要一小部分的活动运动神经元进行准确采样。以这种方式，中枢神经系统可以直接将振荡的控制信号传输到肌肉，几乎是功能相关力的整个范围。
Non-technical summarySince the human central nervous system controls muscle contraction through inputs to spinal motoneurons, oscillations recorded on the primary motor cortex during voluntary movements are correlated with the electrical activity produced on the surface of the muscles. We show through theoretical derivations and experimental recordings that cortical input is transmitted partly in a linear way to the population of motoneurons. The results demonstrate the effective spread of the cortical projections to the motoneuron pool to allow an efficient control of the muscle force output.Oscillations in the primary motor cortex are transmitted through the corticospinal tract to the motoneuron pool. This transmission has been previously investigated using coherence analysis between concurrent recordings of EEG and surface EMG signals. In this study we used a mathematical derivation and motor unit recordings in vivo to investigate the origin of linear transmission of cortical input to the motoneuron spike trains (neural drive to muscle). The theoretical derivation showed that a common input spread to a relatively small number of motoneurons is partly transmitted in a linear way, overcoming the interference signal generated by the non-linearity of the individual motoneurons. We further calculated the corticomuscular coherence between experimental EEG signals and the cumulative spike trains of motor units in the abductor digiti minimi muscle of seven healthy men. The experimental results indicated that, on average, only four to five motor units were sufficient to reach the same level of coherence as estimated from the surface EMG. The results demonstrate that linearity in the transmission of the cortical input to motoneurons through the corticospinal tract is achieved because (i) this input is largely common to all motoneurons, and (ii) its frequency content requires only a small fraction of active motoneurons to be accurately sampled. In this way, the central nervous system can directly transmit oscillations to the control signals to muscles for practically the entire range of functionally relevant forces.