The electroencephalography (EEG) and evoked potential data were recorded from a Neuroscan 64-Channel Quick-Cap (El Paso, TX, USA). All electrodes were placed according to the international 10–20 electrode placement standard. Two external electro-oculogram electrodes were used to monitor vertical and horizontal eye movements. Raw data were acquired with Neuroscan Synamps 2 amplifiers at a sampling rate of 1 kHz.
