[ACTIVE AND PASSIVE DISCRIMINATION OF MOVING SOUNDS: EVENT-RELATED RESPONSES OF HUMAN BRAIN]

The current study investigates auditory event-related potentials (ERPs) and mismatch negativity (MMN) during active and passive discrimination of stationary and moving sound stimuli presented according to the oddball paradigm. Standard stimuli represented stationary midline sounds. Deviant stimuli simulated sound source location shifts (to the left/right from head midline) produced by linear or stepwise changes of interaural time delay (ITD). The event-related responses were evaluated by peak amplitudes of N1 waves and mean amplitudes of MMN, P3a, P3b and reorienting negativity (RON) components. The N1 amplitude was larger in active than in passive conditions, and was unaffected by spatial dynamic changes of the deviant stimuli. The deviant motion pattern (smooth or stepwise) affected only MMN and RON obtained in passive listening conditions. Abrupt deviant displacement elicited larger MMN and RON components than smooth motion. Drawing listeners' attention to the deviant stimuli resulted in suppression of MMN/RON sensitivity to auditory motion pattern.