The resting EEG data were divided into 2 s half-overlapping epochs (i.e. the first second of each epoch overlapped with the last second of the preceding epoch). Epochs in which EOG amplitude >60µV were eliminated from further processing. Fast Fourier Transform (FFT) was then applied to each artifact-free epoch using a Tukey-Hanning window, resulting in power spectra with 0.5 Hz resolution. The mean absolute power within the Beta frequency range (13–30 Hz) was then calculated for each of the three recording sites. Because the distributions of power within these bands were skewed, the data were log transformed.
