Centre for Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Department of Neurology/Clinical Neurophysiology, Nijmegen, The Netherlands.
Clin Neurophysiol. 2010 Oct;121(10):1633-42. doi: 10.1016/j.clinph.2010.03.052.
Investigate the effectiveness and frequency dependence of central drive transmission via the alpha-motoneuron pool to the muscle.
We describe a model for the simulation of alpha-motoneuron firing and the EMG signal as response to central drive input. The transfer in the frequency domain is investigated. Coherence between stochastical central input and EMG is also evaluated.
The transmission of central rhythmicities to the EMG signal relates to the spectral content of the latter. Coherence between central input to the alpha-motoneuron pool and the EMG signal is significant whereby the coupling strength hardly depends on the frequency in a range from 1 to 100 Hz. Common central input to pairs of alpha-motoneurons strongly increases the coherence levels. The often-used rectification of the EMG signal introduces a clear frequency dependence.
Oscillatory phenomena are strongly transmitted via the alpha-motoneuron pool. The motoneuron firing frequencies do play a role in the transmission gain, but do not influence the coherence levels. Rectification of the EMG signal enhances the transmission gain, but lowers coherence and introduces a strong frequency dependency. We think that it should be avoided.
Our findings show that rhythmicities are translated into alpha-motoneuron activity without strong non-linearities.
研究通过α运动神经元池向肌肉传递中枢驱动的有效性和频率依赖性。
我们描述了一个模拟α运动神经元放电和肌电图信号作为中枢驱动输入响应的模型。在频域中研究了传递。还评估了随机中枢输入和肌电图之间的相干性。
中枢节律向肌电图信号的传递与后者的频谱内容有关。α运动神经元池的中枢输入与肌电图信号之间的相干性具有显著性，耦合强度在 1 至 100 Hz 的范围内几乎不依赖于频率。对成对的α运动神经元的共同中枢输入大大增加了相干水平。肌电图信号的常用整流会引入明显的频率依赖性。
振荡现象通过α运动神经元池强烈传递。运动神经元的放电频率确实在传输增益中起作用，但不影响相干水平。肌电图信号的整流增强了传输增益，但降低了相干性并引入了强烈的频率依赖性。我们认为应该避免这种情况。
我们的发现表明，节律性活动在没有强烈非线性的情况下转化为α运动神经元活动。
