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Titolo:
Activation of medial olivocochlear efferent system in humans: influence ofstimulus bandwidth
Autore:
Maison, S; Micheyl, C; Andeol, G; Gallego, S; Collet, L;
Indirizzi:
Univ Lyon 1, Lab Neurosci & Syst Sensoriels, UPRESA CNRS 5020, F-69365 Lyon, France Univ Lyon 1 Lyon France F-69365 , UPRESA CNRS 5020, F-69365 Lyon, France
Titolo Testata:
HEARING RESEARCH
fascicolo: 1-2, volume: 140, anno: 2000,
pagine: 111 - 125
SICI:
0378-5955(200002)140:1-2<111:AOMOES>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
EVOKED OTOACOUSTIC EMISSIONS; COCHLEAR MICROMECHANICAL PROPERTIES; CONTRALATERAL ACOUSTIC STIMULATION; AUDITORY-NERVE FIBERS; INTENSITY DISCRIMINATION; MODULATED TONES; MASKED TONES; BUNDLE; NOISE; NEURONS;
Keywords:
bandwidth; cochlea; human; medial olivocochlear efferent; noise; otoacoustic emission;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Maison, S Hop Edouard Herriot, Pavillon U,3 Pl Arsonval, F-69437 Lyon 03, France Hop Edouard Herriot Pavillon U,3 Pl Arsonval Lyon France 03 nce
Citazione:
S. Maison et al., "Activation of medial olivocochlear efferent system in humans: influence ofstimulus bandwidth", HEARING RES, 140(1-2), 2000, pp. 111-125

Abstract

The activity of the medial olivocochlear bundle (MOCB) can be studied in humans through variations in the level of evoked otoacoustic emissions (EOAEs) elicited by contralateral acoustic stimuli (CAS). The present study sought to investigate how the activity of the MOC system at a given frequency! as measured through the contralateral suppression of tone-pip EOAEs, depends on the bandwidth of the contralateral stimulus. EOAEs were recorded in 155 normal-hearing subjects, successively with and without contralateral stimuli whose bandwidth, center frequency and level were systematically varied. We showed a dear dependence of contralateral EOAE suppression on bandwidthdemonstrating increased suppression with increased bandwidth over about two octaves around the center frequency of the noise. This effect was obtained irrespective of whether contralateral noise energy was kept constant independently of bandwidth or not, which indicates a role of bandwidth per se in contralateral EOAE suppression. Results are interpreted in terms of a simple model of MOCB activation mechanisms including peripheral bandpass filtering, within-channel compression and across-channel spatial summation by the afferent paths. Complementary experiments suggested a greater-effectiveness of increases in bandwidth on the upper than on the lower side and of frequency components akin to or remote from the test frequency than of intermediate bands. Finally; these results were complemented by detailed spectrum analyses of the EOAE level variations induced by the different noises, which revealed that whilst noise components close to or remote from the center frequency generally attenuated EOAE level, intermediate components could insome cases lead to a relative increase in EOAE level. These results can further be explained by assuming different positive and negative weights on the inputs to the spatial summation process depending on their position relative to the center frequency. (C) 2000 Elsevier Science B.V. All rights reserved.

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Documento generato il 04/12/20 alle ore 09:12:02