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Behavioral Measures of Cochlear Gain Reduction Depend on Precursor Frequency, Bandwidth, and Level

Sensory systems adjust to the environment to maintain sensitivity to change. In the auditory system, the medial olivocochlear reflex (MOCR) is a known physiological mechanism capable of such adjustment. The MOCR provides efferent feedback between the brainstem and cochlea, reducing cochlear gain in...

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Autores principales: DeRoy Milvae, Kristina, Strickland, Elizabeth A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8520990/
https://www.ncbi.nlm.nih.gov/pubmed/34671236
http://dx.doi.org/10.3389/fnins.2021.716689
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author DeRoy Milvae, Kristina
Strickland, Elizabeth A.
author_facet DeRoy Milvae, Kristina
Strickland, Elizabeth A.
author_sort DeRoy Milvae, Kristina
collection PubMed
description Sensory systems adjust to the environment to maintain sensitivity to change. In the auditory system, the medial olivocochlear reflex (MOCR) is a known physiological mechanism capable of such adjustment. The MOCR provides efferent feedback between the brainstem and cochlea, reducing cochlear gain in response to sound. The perceptual effects of the MOCR are not well understood, such as how gain reduction depends on elicitor characteristics in human listeners. Physiological and behavioral data suggest that ipsilateral MOCR tuning is only slightly broader than it is for afferent fibers, and that the fibers feed back to the frequency region of the cochlea that stimulated them. However, some otoacoustic emission (OAE) data suggest that noise is a more effective elicitor than would be consistent with sharp tuning, and that a broad region of the cochlea may be involved in elicitation. If the elicitor is processed in a cochlear channel centered at the signal frequency, the growth of gain reduction with elicitor level would be expected to depend on the frequency content of the elicitor. In the current study, the effects of the frequency content and level of a preceding sound (called a precursor) on signal threshold was examined. The results show that signal threshold increased with increasing precursor level at a shallower slope for a tonal precursor at the signal frequency than for a tonal precursor nearly an octave below the signal frequency. A broadband noise was only slightly more effective than a tone at the signal frequency, with a relatively shallow slope similar to that of the tonal precursor at the signal frequency. Overall, these results suggest that the excitation at the signal cochlear place, regardless of elicitor frequency, determines the magnitude of ipsilateral cochlear gain reduction, and that it increases with elicitor level.
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spelling pubmed-85209902021-10-19 Behavioral Measures of Cochlear Gain Reduction Depend on Precursor Frequency, Bandwidth, and Level DeRoy Milvae, Kristina Strickland, Elizabeth A. Front Neurosci Neuroscience Sensory systems adjust to the environment to maintain sensitivity to change. In the auditory system, the medial olivocochlear reflex (MOCR) is a known physiological mechanism capable of such adjustment. The MOCR provides efferent feedback between the brainstem and cochlea, reducing cochlear gain in response to sound. The perceptual effects of the MOCR are not well understood, such as how gain reduction depends on elicitor characteristics in human listeners. Physiological and behavioral data suggest that ipsilateral MOCR tuning is only slightly broader than it is for afferent fibers, and that the fibers feed back to the frequency region of the cochlea that stimulated them. However, some otoacoustic emission (OAE) data suggest that noise is a more effective elicitor than would be consistent with sharp tuning, and that a broad region of the cochlea may be involved in elicitation. If the elicitor is processed in a cochlear channel centered at the signal frequency, the growth of gain reduction with elicitor level would be expected to depend on the frequency content of the elicitor. In the current study, the effects of the frequency content and level of a preceding sound (called a precursor) on signal threshold was examined. The results show that signal threshold increased with increasing precursor level at a shallower slope for a tonal precursor at the signal frequency than for a tonal precursor nearly an octave below the signal frequency. A broadband noise was only slightly more effective than a tone at the signal frequency, with a relatively shallow slope similar to that of the tonal precursor at the signal frequency. Overall, these results suggest that the excitation at the signal cochlear place, regardless of elicitor frequency, determines the magnitude of ipsilateral cochlear gain reduction, and that it increases with elicitor level. Frontiers Media S.A. 2021-10-04 /pmc/articles/PMC8520990/ /pubmed/34671236 http://dx.doi.org/10.3389/fnins.2021.716689 Text en Copyright © 2021 DeRoy Milvae and Strickland. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
DeRoy Milvae, Kristina
Strickland, Elizabeth A.
Behavioral Measures of Cochlear Gain Reduction Depend on Precursor Frequency, Bandwidth, and Level
title Behavioral Measures of Cochlear Gain Reduction Depend on Precursor Frequency, Bandwidth, and Level
title_full Behavioral Measures of Cochlear Gain Reduction Depend on Precursor Frequency, Bandwidth, and Level
title_fullStr Behavioral Measures of Cochlear Gain Reduction Depend on Precursor Frequency, Bandwidth, and Level
title_full_unstemmed Behavioral Measures of Cochlear Gain Reduction Depend on Precursor Frequency, Bandwidth, and Level
title_short Behavioral Measures of Cochlear Gain Reduction Depend on Precursor Frequency, Bandwidth, and Level
title_sort behavioral measures of cochlear gain reduction depend on precursor frequency, bandwidth, and level
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8520990/
https://www.ncbi.nlm.nih.gov/pubmed/34671236
http://dx.doi.org/10.3389/fnins.2021.716689
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