Our electroencephalography (EEG) system (actiCHamp, Brain Products) consists of 128 active scalp electrodes, several passive electrodes to be used for electrooculography (EOG), and a StimTrak unit allowing to record audio signals along with the EEG signals. For auditory stimulus presentation, we use insert earphones (ER-2; Etymotic Research) minimizing electric noise induction and providing a large audio bandwidth.