Enhancing interaural-delay-based extents of laterality at high frequencies by using "transposed stimuli".
An acoustic pointing task was used to determine whether interaural temporal disparities (ITDs) conveyed by high-frequency "transposed" stimuli would produce larger extents of laterality than ITDs conveyed by bands of high-frequency Gaussian noise. The envelopes of transposed stimuli are designed to provide high-frequency channels with information similar to that conveyed by the waveforms of low-frequency stimuli. Lateralization was measured for low-frequency Gaussian noises, the same noises transposed to 4 kHz, and high-frequency Gaussian bands of noise centered at 4 kHz. Extents of laterality obtained with the transposed stimuli were greater than those obtained with bands of Gaussian noise centered at 4 kHz and, in some cases, were equivalent to those obtained with low-frequency stimuli. In a second experiment, the general effects on lateral position produced by imposed combinations of bandwidth, ITD, and interaural phase disparities (IPDs) on low-frequency stimuli remained when those stimuli were transposed to 4 kHz. Overall, the data were fairly well accounted for by a model that computes the cross-correlation subsequent to known stages of peripheral auditory processing augmented by low-pass filtering of the envelopes within the high-frequency channels of each ear.
Bernstein
Leslie R
LR
Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030, USA. les@neuron.uchc.edu
Trahiotis
Constantine
C
D000328:Adult; D004007:Dichotic Listening Tests; D005260:Female; D006801:Humans; D008144:Loudness Perception; D008297:Male; D015233:Models, Statistical; D016011:Normal Distribution; D010469:Perceptual Distortion; D010470:Perceptual Masking; D010897:Pitch Discrimination; D011930:Reaction Time; D017603:Signal Detection, Psychological; D013017:Sound Localization; D013018:Sound Spectrography; D013223:Statistics as Topic