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 of resting EEG data. All impedances were kept under 10K Ohms. Data were collected using 1000 Hz sampling rate, amplified 2816 times, and filtered with a 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 reference modes: the average of all EEG leads (AVG), Cz, averaged (“linked”) mastoids (LM), and to the reference-free current source density transformation (CSD; using algorithms from Kayser & Tenke, 2006, and based on the spherical spline approach summarized by Perrin, Pernier, Bertrand, and Echallier, 1989, 1990; although CSD is technically reference-free, it will be referred to as a reference mode to streamline description of analyses and results).
