Institute of Rehabilitation Engineering and Technology, School of Medical Device and Food Engineering, Biomedical Engineering.
Shanghai Engineering Research Center of Assistive Devices, University of Shanghai for Science and Technology, Shanghai.
Neuroreport. 2020 Mar 4;31(4):338-345. doi: 10.1097/WNR.0000000000001409.
Bilateral voluntary contractions involve functional changes in both primary motor cortices. However how the unilateral voluntary contraction of hand muscles influences the contralateral corticomuscular synchronous oscillations mechanisms remains unclear. In the bimanual tasks, nine healthy subjects were instructed to generate force by abducting their left-hand index finger against a force sensor and simultaneously the right-hand precise pinch task with visual feedback. They were divided into four conditions according to the two contraction force levels of the left-hand muscles 5% and 50% maximal isometric voluntary contraction (MVC) and with/without visual feedback for the right hand. Corticomuscular synchronization of the right hand in the beta band was revealed when the subjects performed the bimanual exercise with 5% MVC of left-hand muscles, which is consistent with previous studies. As the contraction strength of the left-hand muscle increased to 50% MVC, the corticomuscular coherence (CMC) frequency of the right hand shifted to gamma band, and the CMC in beta band decreased significantly (P < 0.05) in the electroencephalography→electromyography direction. This phenomenon suggests that the corticomuscular synchronous oscillation will shift from beta band to higher frequencies (principally gamma) as the contraction force of the contralateral hand increases, which may be due to the changes in the subject's attention and more frequent synchronization of neuromuscular motor neurons oscillations. These findings will be helpful to explore the hand motion control and feedback mechanisms, and further provide a basis for the application of neuromuscular coupling in clinical rehabilitation evaluation.Video abstract: http://links.lww.com/WNR/A571.
双侧随意收缩涉及初级运动皮层的功能变化。然而，手肌的单侧随意收缩如何影响对侧皮质肌同步振荡机制尚不清楚。在双手任务中，9 名健康受试者被指示通过伸展左手食指来对抗力传感器产生力，并同时进行右手精确捏合任务，具有视觉反馈。根据左手肌肉的两种收缩力水平（5%和 50%最大等长自愿收缩（MVC））以及右手是否具有视觉反馈，将他们分为四个条件。当受试者以 5%的左手肌肉 MVC 进行双手运动时，右手在β波段显示出皮质肌同步性，这与之前的研究一致。当左手肌肉的收缩力增加到 50%MVC 时，右手的皮质肌相干（CMC）频率转移到γ波段，并且脑电图→肌电图方向的β波段 CMC 显著降低（P < 0.05）。这一现象表明，随着对侧手部收缩力的增加，皮质肌同步振荡将从β波段转移到更高频率（主要是γ），这可能是由于受试者注意力的变化和神经肌肉运动神经元振荡更频繁的同步所致。这些发现将有助于探索手部运动控制和反馈机制，并为神经肌肉耦合在临床康复评估中的应用提供依据。视频摘要：http://links.lww.com/WNR/A571.
