Fig. 2.

Blink validation analyses indicate no significant group differences in blink number, latency, or ERP amplitude in raw and cleaned EOG data. (a) Histogram of blink latency shows probabilistic distribution of blink occurrence within a trial. Each bin is 100 ms and the sum of all binned values is 1 for each group. There were no significant group differences in blink count or latency. (b) A whole-head topography at the the blink ERP peak (group average = 488 ms) and locations of five frontal EEG electrodes used for analysis. (c) Blink ERP of minimally-processed raw data (see Supplemental Materials S5) show no significant group difference in ERP mean peak-window amplitude (indicated by dark line above the ERP peak). The dotted line (~0 uV) shows the back projected potentials at the same frontal electrodes from the three frontal EOG-IC clusters, which account for 13% of total ICs but 93% of the blink ERP. (d) Magnification (57×) of the cleaned EOG-IC data indicates overlap of the blink ERP for both groups. CTD = Chronic Tic Disorder, HC=Healthy Control, ERP = event related potential, EOG = Electroculography, IC = independent component.