EEG Data Collection and Analysis for Color-Matching Task

EEG data were collected in the one-back color-matching task only. The EEG signal was recorded from 30 Ag/AgCl electrodes secured in an elastic cap according to the extended 10–20 system. The EEG data were recorded with a BrainAmp amplifier system and the software for EEG recording was Brain Vision Recorder (Brain Products GmbH, Germany). The Cz electrode served as an online reference, but the data were offline re-referenced to the average. Horizontal EOG was recorded in a bipolar lead from two additional electrodes placed on the outer canthi of the two eyes. Vertical EOG was recorded in a bipolar lead from additional electrodes placed on the supra-orbital and infra-orbital ridges of the right eye. The electrode impedance was kept below 5 kΩ. The EEG and EOG signal were continuously recorded and amplified at a sampling rate of 1000 Hz, with a band pass from AC 0.1 to 100 Hz.
In the offline analysis, the EEG signal was first low-pass filtered at 30 Hz and automatically scanned for artifacts in EEGLab (Delorme and Makeig, 2004 (link)), an open-source EEG data analysis toolbox implemented in MATLAB. Using the default parameters of the SASICA toolbox (Chaumon et al., 2015 (link)), eye movement artifacts in the EEG signal were removed with an ICA-based procedure (Delorme et al., 2012 (link)).