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This Article Full Text Full Text (PDF) All Versions of this Article: 102/2/724    most recent 00129.2009v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Dent, M. L. Articles by Yin, T. C. T. PubMed PubMed Citation Articles by Dent, M. L. Articles by Yin, T. C. T.

Influence of Sound Source Location on the Behavior and Physiology of the Precedence Effect in Cats

¹Department of Physiology and ⁴Neuroscience Training Program, University of Wisconsin, Madison, Wisconsin; ²Department of Psychology, University at Buffalo, The State University of New York, Buffalo, New York; and ³Department of Physiology and Biophysics, University of Colorado Health Sciences Center, Aurora, Colorado

Submitted 12 February 2009; accepted in final form 6 May 2009

Psychophysical experiments on the precedence effect (PE) in cats have shown that they localize pairs of auditory stimuli presented from different locations in space based on the spatial position of the stimuli and the interstimulus delay (ISD) between the stimuli in a manner similar to humans. Cats exhibit localization dominance for pairs of transient stimuli with |ISDs| from 0.4 to 10 ms, summing localization for |ISDs| < 0.4 ms and breakdown of fusion for |ISDs| > 10 ms, which is the approximate echo threshold. The neural correlates to the PE have been described in both anesthetized and unanesthetized animals at many levels from auditory nerve to cortex. Single-unit recordings from the inferior colliculus (IC) and auditory cortex of cats demonstrate that neurons respond to both lead and lag sounds at ISDs above behavioral echo thresholds, but the response to the lag is reduced at shorter ISDs, consistent with localization dominance. Here the influence of the relative locations of the leading and lagging sources on the PE was measured behaviorally in a psychophysical task and physiologically in the IC of awake behaving cats. At all configurations of lead-lag stimulus locations, the cats behaviorally exhibited summing localization, localization dominance, and breakdown of fusion. Recordings from the IC of awake behaving cats show neural responses paralleling behavioral measurements. Both behavioral and physiological results suggest systematically shorter echo thresholds when stimuli are further apart in space.