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 a bipolar horizontal EOG as the signal. Epochs spanning − 2 to 2 seconds relative to stimulus-onset were assessed for artifact using similar criteria as in our initial step. Artifact-contaminated electrodes or electrode/epochs were interpolated using a spherical-spline method (Perrin et al., 1989). Trials on which >15% of electrodes required interpolation were dropped.
