Examination of neural control mechanism behind voluntary contraction of upper and lower limb muscles by using corticomuscular coherence analysis

为了了解我们的大脑是如何控制我们的随意运动的，我通过测量感觉运动皮层的脑电图（EEG）信号和对侧肢体肌肉在强直等长随意收缩期间的肌电图（EMG）信号之间的一致性，研究了功能性皮质-肌肉耦合。结果表明：(1)脑电图-肌电图相干程度存在肌肉依赖性；即下肢远端肌肉表现出最大的一致性；(2)训练良好的运动员（如芭蕾舞演员和举重运动员）的脑电图-肌电相干性幅度小于未经训练的被试；(3)不同肌肉收缩水平增加对脑电图-肌电相干性的调节模式不同。

To know how our brain controls our voluntary movements, I have examined the functional corticomuscular coupling by measuring coherence between electroencephalogram (EEG) signals over the sensorimotor cortex and electromyogram (EMG) signals of contralateral limb muscles during tonic isometric voluntary contraction. Obtained results were that : (1) there existed muscle dependency of the magnitude of EEG-EMG coherence ; i.e., the distal lower limb muscles showed largest coherence ; (2) the magnitude of EEG-EMG coherence was smaller in well-trained athletes, such as ballet-dancers and weightlifters, than in untrained subjects ; (3) Modulation patterns of EEG-EMG coherence by increasing contraction levels were different between muscles.