Effect of Motion Trajectory on the Lateralization of Auditory Evoked Responses.

Processing of acoustic space in the human auditory system implicates the interaction of the left and right hemispheres of the brain. In this study, we investigated the influence of the position and motion direction of sound stimuli on the amplitude and latency of N1, P2, MMN, and P3a components of auditory evoked potentials in the left and right brain hemispheres. The data suggest that functional asymmetry of the N1P2 complex and difference waveforms can be described as weak contralateral dominance. Deviants moving from the lateral positions evoked later P3a components than those moving from the midline, which is consistent with the concept of higher localization accuracy in the frontal part of the acoustic space. The motion direction affected the MMN and P3a latency: the centrifugal deviants produced earlier MMN and P3a responses than the centripetal deviants. This could result from a stronger orienting reaction caused by stimuli moving from the center towards the periphery as compared with the opposite direction. [ABSTRACT FROM AUTHOR]