The electrodes were placed according to the 10-20 System (Fp1, Fpz, Fp2, F7, F3, Fz, F4, F8, T7, C3, Cz, C4, T8, P7, P3, Pz, P4, P8, O1, Oz, and O2). Additional intermediate sites were FC5, FC1, FC2, FC6, CP5, CP1, CP2, CP6, PO3, POz, PO4). All channels were referenced to linked mastoids and had an impedance of ≤10 kΩ, the ground electrode was located at the nasion. An additional channel was used for electrooculography (EOG) recording. The EEG data recorded at each electrode was amplified with a band pass filter of 0.5–30 Hz.
