EEG data collection Each EEG recording session ran for 10 min (4 min with eyes closed, 2 min with eyes open, and 4 min with eyes closed) as participants sat on a comfortable chair in a shielded room with dim lights. The participants were instructed to avoid drowsiness and movement during the data acquisition period. EEG activity was recorded from 64 sites using Ag/AgCl electrodes based on the modified International 10–20 system in conjunction with vertical and horizontal electrooculograms (EOGs) and one bipolar reference electrode (mastoid). The EEG channels were acquired and amplified at a sampling rate of 1000 Hz (Scan 4.5, Neuroscan, Compumedics; El Paso, TX, USA) using a 0.1–100 Hz online bandpass filter and a 0.1–50 Hz offline bandpass filter. Electrode impedances were kept below 5 kΩ.All EEG data were analyzed with Neuroguide (NG) Deluxe 2.6.1 software (Applied Neuroscience; St. Petersburg, FL, USA). Thatcher et al. reported that, compared to an average reference and the Laplacian reference, the linked ears (LE) reference is suitable for coherence analyses60. Thus, the following 19-channel montage with LE references was adopted for
