The power spectral density (PSD) was calculated by the Welch method implemented in MATLAB. To be comparable with the movement-related PAC, the PSD was calculated in 300 ms shifted windows with 50 ms time steps in 3-s epochs (Hann window, frequency resolution 1 Hz) for all conditions. Then, PSD was transformed to base 10 logarithmic power for group comparison and presentation. The power was normalized by subtracting the mean power across all time points and trials from 4 to 300 Hz (excluding 50 Hz and its harmonics) to account for the intersubject variability.
