The g.BCIsys64USB EEG system, manufactured by g.tec GmBH, uses wide-range DC-coupled amplifier technology with 24-bit sampling, which results in an input voltage resolution of < 30 nV. Very efficient analog-to-digital converters (2.5 MHz per channel) result in very high signal to noise ratio, critical for recording subtle changes in EEG measures. The system combines four bio-amplifiers (16-channels each) that can either be stacked to provide a higher density (32/48/64 channels) system, or can simultaneously be used on different study participants. The EEG system makes use of 'active' electrode technology that employs an additional ultra-low noise pre-amplifier located inside each electrode to maximize the signal-to-noise ratio. The active electrodes work in a frequency range from 0 - 10 kHz (DC) or 0.1 - 10 kHz (AC). The EEG system is also equipped with innovative data acquisition and data analysis software that allows sophisticated signal processing and data analysis capabilities. The system includes a 3D scalp digitizer that maps the scalp in the stereotactic space for EEG source localization. Other capabilities of the system include eye-tracking and acquisition of physiological data (SpO2, pulse and skin conductance).