We employed the Welch periodogram method (Python MNE function psd_welch23) to calculate power spectral density using a fast Fourier transform of 512 points. This rendered a frequency resolution of 1.95 Hz. A 50% overlap using a Hanning window was used to reduce edge effects. Power spectral density was transformed into the log scale. In the computation of the beta (13–30 Hz) and gamma (50–200 Hz) power, a further inner-subject normalization was made by calculating the percentage of the total power in each subject.
