An Event-Related Study for Dynamic Analysis of Corticomuscular Connectivity

Corticomuscular coupling estimated by EEG-EMG coherence may reveal functional cortical driving of peripheral muscular activity. EEG-EMG coherence in the beta band (15–30 Hz) has been extensively studied under isometric muscle contraction tasks. We attempted to study the time-course of corticomuscular connectivity under a dynamic target tracking task. A new device was developed for the real-time measurement of dynamic force created by pinching thumb and index fingers. Four healthy subjects who participated in this study were asked to track visual targets with the feedback forces. Spectral parameters using FFT and complex wavelet were explored for reliable estimation of event-related coherence and EEG-EMG correlogram for representing corticomuscular connectivity. Clearly distinguishable FFT-based coherence and cross-correlogram during the visual target tracking were observed with appropriate hyper-parameters for spectral estimation. The system design and the exploration of signal processing methods in this study supports further exploration of corticomuscular connectivity associated with human motor control.