Similarly, the lower coherence of the corrected T7*Cz cannot be reflected by the higher coherence of the referential F7*Pz from 20 to 30 Hz. Comparing the MSC in Fig. 5(D) and the spectral power in Fig. 5(A), one can see that T7 and F7 have isolated power peaks at 9 Hz and T7*F7 has a consistent coherence peak at 9 Hz. However, no peaks can be found for the bipolar EEG (F7–T7)*(Cz–Pz) in Fig. 5(A) and bipolar EEG F7–T7 in Fig. 5(A) at the same frequency. The corrected F7 has a power peak at 27.5 Hz, and the corrected F7*Cz, F7*Pz, and T7*F7 also have consistent isolated coherence peaks at 27.5 Hz. However, no peaks can be found for the referential F7*Cz, F7*Pz, and T7*F7, the bipolar EEG (F7–T7)*(Cz–Pz) in Fig. 5(D), and the referential F7 and bipolar EEG F7–T7 in Fig. 5(A) at the same frequency. Hence, the referential and bipolar EEGs may hinder the appearance of peaks in the corrected EEG in spectral-power and coherence analyses.
