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New Experiments Employing Raised-Sine Stimuli Suggest an Unknown Factor Affects Sensitivity to Envelope-Based ITDs for Stimuli Having Low Depths of Modulation

Conference paper

Abstract

This chapter reports an extension of work reported at the previous ISH meeting wherein threshold interaural temporal disparities (ITDs) were measured with high-frequency, raised-sine stimuli. The threshold ITDs reported here were obtained while varying, independently and parametrically, the depth of modulation, the frequency of modulation, and the value of the exponent of the raised-sine stimuli (which affects the relative “peakedness/dead-time” of their envelopes). Graded increases in the exponent led to graded decreases in threshold ITD for frequencies of modulation ranging from 32 to 256 Hz. Thresholds also generally increased with decreases in modulation depth. Unexpectedly, however, variations of the exponent of the raised sine interacted with variations in depth of modulation such that smaller increases in threshold ITD occurred for decreases in the depth of modulation when the exponent was large. This interaction proved interesting because an interaural correlation-based model that is generally able to account for changes in threshold ITD produced by separate changes in exponent, depth of modulation, and frequency of modulation of raised-sine stimuli could not account for the interaction. The magnitudes of the psychophysically measured effects suggest that it would be beneficial and important that auditory physiologists conduct parallel investigations while employing similar raised-sine stimuli.

Keywords

Raised-cosine stimuli Inter-aural time difference Binaural hearing Modulation Envelope information 

Notes

Acknowledgments

This research was supported by research grants NIH DC-04147 and DC-04073 from the National Institute on Deafness and Other Communication Disorders, National Institutes of Health.

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Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Deptartments Of Neuroscience and Surgery (Otolaryngology)University of Connecticut Health CenterFarmingtonUSA

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