EEG was performed using the 64-channel Geodesic Sensor Net connected to a 64-channel high-input impedance amplifier (Net Amp 300; Electrical Geodesics, Eugene, OR, USA) in a soundproofed and electrically shielded experimental room. Resting EEG activity was recorded for 6 min in two 3-min recordings with eyes closed. All electrodes were referenced to Cz and impedance was maintained at ≤50 kΩ (Tucker, 1993). EEG activity was recorded continuously using a 0.1–100 Hz bandpass filter and a sampling rate of 500 Hz. Collected EEG data were digitally filtered using a 0.3–30 Hz bandpass filter and re-referenced to the average reference. Artifacts such as eyeblinks were removed based on the threshold of the peak-to-peak amplitude of ±100 μV from the eye channels. To conduct spectrum and FC analyses, events were selected by dividing the continuously measured EEG into 500-ms epochs and performing window sliding in each of the epochs at an interval of 250 ms. The data is displayed in units of 2 Hz in frequency, in these 500-ms epochs. For example, theta band is calculated by averaging the values of 4 Hz
