Electroencephalography acquisition and preprocessing

Continuous EEG was recorded using a 32-channel BrainVision ActiCap active electrode system (BrainProducts GmbH, Germany) during resting conditions in which participants were required to stay awake, but with their eyes closed. Signals were bandpass filtered between 0.05 and 100 Hz and sampled at 500 Hz. Impedances for each channel were maintained below 5 KΩ before recording. The reference electrode was located at FCz and the ground electrode at AFz. During the eyes-closed rsEEG recording, participants were seated comfortably in a dimly lit, sound-proof experimental room. The rsEEG recording lasted for 5 min and was implemented before the behavioral tasks.

Offline EEG data preprocessing were performed using EEGLAB toolbox (version 14.1.1; Delorme and Makeig, 2004) and customized MATLAB (The MathWorks, Inc., Natick, United States) scripts. First, the continuous EEG data were re-referenced to the averaged mastoids, band-pass filtered between 1 and 40 Hz (50 Hz notched) with a linear finite impulse response (FIR) filter, and segmented into non-overlapping 2 s epochs. Subsequently, large artifacts (i.e., muscular artifacts, eye movements, eye blinks, etc.) were rejected manually by visual inspection. Further, the independent component analysis (ICA) and the automatic raw data inspection (max amplitude: ± 80 uV) were consecutively performed to identify and correct for the remaining artifacts. Finally, the artifact-corrected data were manually screened a second time to ensure data purity. On average, 148.26 (SD = 2.62) epochs per participant were selected for further analysis, accounting for 98.8% of the total epochs (150 epochs).