Resting EEG at each session was recorded for eight one-minute baselines of eyes-open (O) and eyes-closed (C), in one of two counterbalanced orders (OCCOCOOC or COOCOCCO). Sessions within day were separated by approximately 20 minutes. All EEG data were collected using a 64-channel NeuroScan Synamps2 amplifier (Charlotte, NC) and acquisition system, utilizing the international 10-20 system for electrode placement. Two electrooculogram (EOG) channels (vertical: superior and inferior orbit of the left eye; lateral: outer canthi) were collected for ocular artifact rejection. All impedances were kept under 10K Ohms. Data for each resting session were digitized continuously at 1000 Hz, amplified 2816 times, and filtered with 200Hz low pass filter prior to digitization. EEG data were acquired with an online reference site immediately posterior to Cz and subsequently re-referenced offline to four different references: 1) average of all EEG leads = AVG, 2) CSD (using algorithms from Kayser & Tenke, 2006 and based on the spherical spline approach summarized by Perrin, Pernier, Bertrand, & Echallier, 1989, 1990), 3) Cz, and 4) averaged (“linked”) mastoids = LM.
