For each subject, continuous EEG was downsampled to 256 Hz and highpass-filtered with a windowed sinc filter (0.1 Hz cutoff, Kaiser window, order of 1286). Gross artifacts, defined as electrode segments in which more than 75% of the samples were contaminated or time segments in which more than 15% of the electrodes were contaminated, were deleted before data were re-referenced to the averaged potential of the earlobe electrodes and lowpass-filtered to remove high-frequency noise (30 Hz cutoff, Kaiser window, order of 644). Artifact-pruned and re-referenced EEG was decomposed with Infomax independent component analysis (Bell and Sejnowski, 1995) for the purpose of correcting blinks and ocular artifacts. Each component’s time course and topographic distribution (inverse-weights) were correlated with the time course of a criterion channel (bipolar vertical electrooculogram, or EOG) and a spatial template (typical inverse-weights of a blink component), respectively. Components with squared correlation-coefficients exceeding threshold derived empirically using an expectation maximization algorithm (Mognon et al., 2011) were considered to represent blink activity and subtracted from the data. Horizontal eye movement artifacts were corrected in a similar manner but with
