Study of brain-machine interface (BMI) uses electroencephalography (EEG) to extract relevant signals of body movement. We aimed to correlate the motor command in EEG and muscle movement represented by electromyography
(EMG) using a time series of each signal. Corresponding components of muscle movement to the brain wave spectrogram representing amotor command is sought through comparison of the EMG power envelope and the wavelet processed EEG. Results showed that the timing and peak of event-related EEG power corresponds to the EMG power envelope in high-gamma bandwidth (55 to 63 Hz) at the primary motor cortex (C3), indicative of phase modulated EEG-EMG connection. Furthermore, EEG poser at the beta wavelength (13~30Hz) exibited anti correlation with EMG.
Such timing and phase coincidence between EEG and EMG suggests event-related synchronization in the primary motor cortex serving as a motor command that initiates muscle activity.