A unifying basis of auditory thresholds based on temporal summation.

Full Abstract

Thresholds of auditory-nerve (AN) fibers and auditory neurons are commonly specified in terms of sound pressure only, implying that they are independent of time. At the perceptual level, however, the sound pressure required for detection decreases with increasing stimulus duration, suggesting that the auditory system integrates sound over time. The quantity commonly believed to be integrated is sound intensity, implying that the auditory system would have an energy threshold. However, leaky integrators of intensity with time constants of hundreds of milliseconds are required to fit the data. Such time constants are unknown in physiology and are also incompatible with the high temporal resolution of the auditory system, creating the resolution-integration paradox. Here we demonstrate that cortical and perceptual responses are based on integration of the pressure envelope of the sound, as we have previously shown for AN fibers, rather than on intensity. The functions relating the pressure envelope integration thresholds and time for AN fibers, cortical neurons, and perception in the same species (cat), as well as for perception in many different vertebrate species, are remarkably similar. They are well described by a power law that resolves the resolution-integration paradox. The data argue for the integrator to be located in the first synapse in the auditory pathway and we discuss its mode of operation.

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Author information

Author/s: Heil, Peter (P); Neubauer, Heinrich (H);

Affiliation: Leibniz Institute of Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany. peter.heil(-atsign-)ifn-magdeburg.de

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A), published in United States. (Language: eng)

Reference: 2003-May; vol 100 (issue 10) : pp 6151-6

Dates: Created 2003/05/14; Completed 2003/07/01; Revised 2008/11/20;

PMID: 12724527, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

Comments and Corrections

ErratumIn: Proc Natl Acad Sci U S A. 2004 Mar 2;101(9):3323.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Animals
Auditory Pathways - physiology
Auditory Threshold - physiology
Cats
Humans

Models, Neurological
Nerve Fibers - physiology
Neurons - physiology
Perception - physiology
Reaction Time - physiology

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