Recordings were collected using a 128-channel Synamps RT amplifier (Neuroscan, Inc.) in conjunction with a Neuroscan 128-channel Quik-cap (sintered Ag-Ag/Cl; non-standard layout [NSL] channel positions). Problems with adequate scalp connection for 10 channels around the ears necessitated removing these channels from the data, which resulted in a total of 112 channels available for analysis. Horizontal and vertical ocular activity was recorded using electrodes positioned on the outer canthus of both eyes and above and below the left eye, respectively. Impedances were kept below 10 k . EEG signals were referenced to the vertex electrode during recording, and rereferenced to averaged mastoid sites offline. Data were collected with an analog 0.05 to 200 Hz bandpass filter, and digitized at 1000 Hz using Neuroscan Acquire 4.5 (Neuroscan, Inc.).
