Visualization of time-frequency components of human movement-related cortical potential using wavelet transform

An electroencephalogram (EEG) has been generally known as a non-destructive method to examine the function of the human brain. This paper presents a method to visualize the time-frequency components of movement-related cortical potential (MRCP) accompanying the human voluntary muscle behavior using a wavelet transform. The EEG was recorded with the 5-channel referential derivations, Fz, Cz, C3,C4, Pz, referenced to the right earlobe based on the international 10-20 system. The voluntary activity was recorded with the electrode placed on the palm side of the metacarpophalangeal joint when the subjects flexed the right-hand index finger with eyes closed. I have found the following insights into the temporal dynamics of MRCP. At about 10 Hz, signals were recorded at all electrodes when the voluntary activity started. The higher level signals of about 10 Hz were recorded at Fz from about 0.4 s after the activity started. About 5 Hz signals appeared at all electrodes from about 1.0 s to 0.2 s before the activity started. Many trials are not needed for this method to visualize the time-frequency components of the MRCP.