We studied the processing of sound location in the human auditory cortex by using spatial stimuli constructed with ILD, ITD, and 3D-sound techniques. The stimulus set comprised wideband (10kHz) noise bursts matched in stimulus duration and loudness. These were presented from eight sound source directions in the azimuthal plane by using 3D sound techniques utilizing either (a) generic (anechoic) HRTFs or (b) individual binaural recordings, or laterally, on the axis between the ears via (c) ILD-, (d) ILD/ITD-, (e) ITD modifications. Auditory N1m responses for stimulus type effects on latency, amplitude, and source location were analyzed. For all stimulus types, the N1m response was always more prominent in the right hemisphere. The ECDs for the 3D sounds were more anteriorly and superficially located than the ECDs of ILD/ITD sounds. The results suggest right-hemispheric specialization in the cortical processing of spatial auditory information. Source location shifts further indicate that the stimulation methods elicit activity in slightly different brain areas.
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