Safri Norlaili Mat, Murayama Nobuki, Igasaki Tomohiko, Hayashida Yuki
Department of Graduate School of Science and Technology, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555, Japan.
Int J Psychophysiol. 2006 Aug;61(2):288-93. doi: 10.1016/j.ijpsycho.2006.03.003. Epub 2006 Apr 27.
The effects of visual stimuli on cortico-spinal synchronization were investigated by measuring the coherence between electroencephalogram (EEG) and electromyogram (EMG) during isometric contraction of the first dorsal interosseous muscle of the right hand. Because a spinal motoneuron and the corresponding muscle fibers form a motor unit with one-to-one correspondence of their action potentials, the EMG indirectly measures the activity of the corresponding spinal neuronal group. The tasks were isometric contraction (Control condition); and isometric contraction with concurrent ignoring of visual stimuli (VS condition). By comparing the Control and VS conditions, the following results were obtained. The coherence increased significantly in magnitude, but was unchanged in frequency range (beta band) and scalp location; the EEG and EMG spectral power in the beta band were unchanged in amplitude; and the alpha and gamma bands of EEG spectral power were significantly increased and decreased, respectively. These findings suggest that the cortico-muscular coherence reflects the cognitive effort needed to maintain isometric muscle contraction. When visual stimuli need to be ignored, the cognitive effort and cortico-spinal coherence are enhanced.
通过测量右手第一背侧骨间肌等长收缩期间脑电图（EEG）和肌电图（EMG）之间的相干性，研究了视觉刺激对皮质-脊髓同步性的影响。由于脊髓运动神经元和相应的肌纤维形成一个运动单位，它们的动作电位一一对应，因此EMG间接测量相应脊髓神经元群的活动。任务包括等长收缩（对照条件）；以及在忽略视觉刺激的同时进行等长收缩（视觉刺激条件）。通过比较对照和视觉刺激条件，得到了以下结果。相干性在幅度上显著增加，但在频率范围（β波段）和头皮位置上没有变化；β波段的EEG和EMG频谱功率在幅度上没有变化；EEG频谱功率的α和γ波段分别显著增加和减少。这些发现表明，皮质-肌肉相干性反映了维持等长肌肉收缩所需的认知努力。当需要忽略视觉刺激时，认知努力和皮质-脊髓相干性会增强。
