The EEG recordings were acquired with a 32-channel MR-compatible BrainAmp system (Brainproducts, Munich, Germany). All the electrodes, integrated into the BrainCap cap, were ring-type sintered nonmagnetic Ag/AgCl electrodes. Twenty-nine EEG electrodes were placed on the scalp according to the 10% system. The reference electrode was positioned in correspondence of the Fcz electrode, between electrodes Fz and Cz. The ground electrode was placed between electrodes Fpz and Fz. Three additional electrodes were dedicated to the acquisition of electrocardiogram (EKG) and electrooculogram (EOG). The impedance was maintained close to 5 kΩ by means of an electrode paste. The resolution and dynamic range of the EEG acquisition system were 100 nV and ± 3.2 mV, respectively. Data were collected with a sampling rate of 5 kHz; band-pass filtering from 0.016 to 250 Hz was applied.
