Human scalp EEG and iEEG are contaminated with multiple noncerebral artifacts including movement artifacts, muscle artifacts, and eye-movement artifacts. We have demonstrated that the reference signal obtained using the approach described previously [1] is a “good” estimation of the real reference signal based on the following four aspects: 1) The referential iEEG muscle artifacts are removed in the corrected iEEG [Fig. 3(A)]; 2) the corrected Cz and Pz contain clear brain activity and muscle artifacts which cannot be seen in the referential Cz and Pz which are close to the reference electrode [Fig. 3(B)]; 3) muscle artifacts in F7 and T7 are reduced after removal of the reference signal [Fig. 3(B)]; 4) the similar high-frequency activity from 20 to 70 Hz of the spectral power for the reference signal and referential iEEG [Fig. 3(C) and (D)] was removed from the spectral power of the corrected iEEG [Fig. 3(E)].
