Tracking of multiple sound sources defined by interaural time differences:: brain potential evidence in humans

Among other cues, interaural time differences (ITD) can be used to compute the location of a sound. To investigate whether ITD can be used for the preattentive detection of sounds coming from a different location than standard sounds (P = 0.7, no ITD), left and right 'far' (900 mus ITD, 80degrees excentricity) and 'near' (300 mus ITD, 30degrees) deviant stimuli (each deviant P = 0.075) were presented via headphones. While 15 young healthy subjects passively listened to these sequences, the mismatch negativity (MMN) of the event-related potential was obtained for the deviant sounds. MMN was reliable for all four deviants but larger for the far-lateralized sounds. Moreover, MMN was larger contralateral to the location of the deviant. This indicates a role of preattentive mechanisms in the spatial analysis of auditory scenes. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.