A 32-channel MR-compatible BrainAmp system (Brainproducts, Munich, Germany) was used for the EEG acquisition. All the electrodes, integrated into the cap, were ring-type sintered nonmagnetic Ag/AgCl electrodes. Twenty-nine EEG electrodes were placed on the scalp according to the 10% system. The physical reference electrode was the Fcz electrode, located between electrodes Fz and Cz. An additional electrode was dedicated to electrocardiogram (EKG), and two other electrodes to electrooculogram (EOG1 and EOG2). An electrode paste (ABRALYT 2000) was used for ensuring current conduction, maintaining the impedance of each electrode close to 5 kΩ. EEG data were collected in the band 0.016–250 Hz with a sampling rate of 5 kHz.
