Corticomuscular coherence analysis on the static and dynamic tasks of hand movement

The synchronization between cortical motor and muscular activity can be revealed by corticomuscular coherence (CMC). This paper designed two neuromuscular activity paradigms of hand movement, i.e. static gripping task and dynamic finger moving task. The electroencephalography (EEG) from C3 and C4 channels and the surface electromyography (sEMG) from the flexor digitorum superficialis were collected simultaneously from 4 male and 4 female right-handed healthy young subjects. For the static griping task, CMCs during low-level forces under 4%, 8%, and 16% MVC (Maximal Voluntary Contraction) were investigated by using magnitude squared coherence calculated from EEGs and sEMGs. For the dynamic finger moving task, the time-frequency domain analysis was used to process dynamic data of temporary action in a period of 2 seconds and get the latency of the maximum CMC. The results of this study indicated that the force increasing within the low-level range in static task is associated with the enhanced CMC. The maximum amplitude of CMC occurred about 0.3-0.5s after the onset of hand movement. Subjects showed significant CMC performance both in static and dynamic task of hand movement.