State Key Laboratory of Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
Clin EEG Neurosci. 2021 Nov;52(6):436-443. doi: 10.1177/1550059420933149. Epub 2020 Jul 1.
The interaction between cortex and muscles under hand motor with different force states has not been quantitatively investigated yet, which to some extent places the optimized movement tasks design for brain-computer interface (BCI) applications in hand motor rehabilitation under uncertainty. Converging evidence has suggested that both the descending corticospinal pathway and ascending sensory feedback pathway are involved in the generation of corticomuscular coupling. The present study aimed to explore the corticomuscular coupling during hand motor task with enhancing force and steady-state force. Twenty healthy subjects performed precision grip with enhancing and static force using the right hand with visual feedback of exerted force. Mutual information and Granger causal connectivity were assessed between electroencephalography (EEG) over primary motor cortex and electromyography (EMG) recordings, and statistically analyzed. The results showed that the mutual information value was significantly larger for static force in the beta and alpha frequency band than enhancing force state. Furthermore, compared with enhancing force, the Granger causal connectivity of descending pathways from cortex to muscle was significantly larger for static force in the beta and high alpha frequency band (10-20 Hz), indicating the connection between the primary motor cortex and muscle was strengthened for static force. In summary, the hand grip with static force resulted in an increasing corticomuscular coupling from EEG over the primary motor cortex to EMG compared with enhancing force, implying more attention was required in the static force state. These results have important implications toward motor rehabilitation therapy design for the recovery of impaired hand motor functions.
目前，尚未对手部在不同力状态下运动时大脑皮层与肌肉之间的相互作用进行定量研究，这在一定程度上使得脑机接口（BCI）应用中针对手部运动康复的优化运动任务设计存在不确定性。越来越多的证据表明，下行皮质脊髓通路和上行感觉反馈通路都参与了皮质肌肉耦合的产生。本研究旨在探索增强力和稳态力手部运动任务中的皮质肌肉耦合。20 名健康受试者使用右手进行精确握力，同时施加视觉反馈力。评估了大脑初级运动皮层的脑电图（EEG）和肌电图（EMG）记录之间的互信息和格兰杰因果连通性，并进行了统计学分析。结果表明，在 beta 和 alpha 频段，静态力的互信息值明显大于增强力状态。此外，与增强力相比，在 beta 和高 alpha 频段（10-20Hz），从皮层到肌肉的下行通路的格兰杰因果连通性在静态力状态下显著增大，表明初级运动皮层和肌肉之间的连接在静态力状态下得到了增强。综上所述，与增强力相比，手部进行静态力握持时，大脑初级运动皮层到 EMG 的皮质肌肉耦合增加，这意味着在静态力状态下需要更多的注意力。这些结果对设计手部运动功能障碍康复治疗方案具有重要意义。
