Mismatch negativity evoked by stationary and moving auditory images of different azimuthal positions.

The present study has been designed to evaluate the pre-attentive detection of the location changes for stationary and moving sound sources. Auditory event-related potentials to the click trains simulating stationary and moving fused auditory images were recorded from healthy subjects using an oddball paradigm. The spatial characteristics of stimuli were created by introducing constant or variable interaural time delay (ITD) into the click trains.

Monaural and binaural perception of approaching and withdrawing auditory images in humans.

Radial motion of the auditory image (approach or withdrawal) was modeled with the help of two loud-speakers placed at different distances from the listener in the anechoic chamber. The thresholds of sound duration for image motion and differential thresholds for its velocity at various azimuthal angles were studied. At azimuthal angles of 0 degrees, 30 degrees, 45 degrees, and 60 degrees, the threshold values of the stimulus durations were 150-200 ms.