| Cochlear outer-hair-cell efferents and complex-sound-induced hearing loss: protective and opposing effects. | |
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MedLine Citation:
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PMID: 11731564 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Centrifugal crossed and uncrossed medial olivocochlear systems (CMOCS and UMOCS) terminate on cochlear outer hair cells (OHCs) and exercise effects through a nicotinic cholinergic receptor. Hence their cochlear effects have not been differentiated. Recent work on protection from loud-sound-induced temporary threshold shifts (TTSs) in hearing sensitivity suggest the two OHC efferent systems may act differently. This was tested, using traumatic complex sound, to determine if such sound could activate both MOCS components and then reveal whether they exerted different effects on TTSs to such stimuli. Traumatic noise bands activated crossed and uncrossed MOCS efferents. Two different CMOCS effects were observed. For frequencies in the noise (within-band frequencies), it protected hearing sensitivity as expected. Novel findings were that at frequencies higher than the noise band range (high-side frequencies), it acted to worsen hearing sensitivity and that this was opposed by a UMOCS effect generally targeted to these frequency regions. It is proposed that the two crossed MOCS actions are extensions of a contrast-enhancement action for low-level noise bands. It is also proposed that the UMOCS plays a state-restoration role to prevent an undesired CMOCS side-effect of exacerbation of high-side TTSs to high-level noise bands. |
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Authors:
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R Rajan |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of neurophysiology Volume: 86 ISSN: 0022-3077 ISO Abbreviation: J. Neurophysiol. Publication Date: 2001 Dec |
Date Detail:
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Created Date: 2001-12-03 Completed Date: 2002-01-28 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0375404 Medline TA: J Neurophysiol Country: United States |
Other Details:
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Languages: eng Pagination: 3073-6 Citation Subset: IM |
Affiliation:
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Department of Physiology, Monash University, Monash, VIC 3800, Australia. ramesh.rajan@med.monash.edu.au |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Acoustic Stimulation Animals Auditory Pathways / physiopathology Cats Cochlea / innervation* Denervation Electrodes, Implanted Hair Cells, Auditory, Outer / physiology* Hearing Loss, Noise-Induced / physiopathology* Neurons, Efferent / physiology* Olivary Nucleus / physiology |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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