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Development and recovery process of noise-induced inner ear damage evaluated by cochlear microhonics in Mongolian gerbils, Meriones unguiculatus

2012; Frontiers Media; Volume: 6; Linguagem: Inglês

10.3389/conf.fnbeh.2012.27.00007

1662-5153

Riquimaroux Hiroshi,

Hearing Loss and Rehabilitation

Event Abstract Back to Event Development and recovery process of noise-induced inner ear damage evaluated by cochlear microhonics in Mongolian gerbils, Meriones unguiculatus Shokei Boku1, Keizo Fukushima1, Kohta I. Kobayasi2, 3, Andrea M. Simmons3, 4, 5, James A. Simmons3, 5 and Hiroshi Riquimaroux1, 2, 3* 1 Graduate School of Life and Medical Sciences, Doshisha University, Department of Biomedical Engineering and Biomedical Information, Graduate School of Life and Medical Sciences, Japan 2 Doshisha University, Department of Biomedical Information, Faculty of Life and Medical Sciences, Japan 3 Doshisha University, Neurosensing and Bionavigation Research Center, Japan 4 Brown University, Department of Cognitive, Linguistic & Psychological Sciences, United States 5 Brown University, Department of Neuroscience, United States Exposure to intense noise results in permanent (PTS) or temporary threshold shifts (TTS). TTS has been reported to reach the maximum 2 min after noise exposure ends in humans. However, it has not been known about growth of TTS in Mongolian gerbils. Because Mongolian gerbil has been an important auditory model rodent, knowing development and recovery process of TTS is useful to understand structural characteristics of inner ear functions. The cochlear microphonics (CM) may serve an excellent tool to physiologically evaluate inner ear functions. Damage to the hair cells is frequency selective depending upon frequency structure and intensity of the sound used for exposure. The location on the basilar membrane and the degree to what extent the damage has been created can be estimated by CM. The purpose of this research was to find out structural characteristics and functions of inner ear of Mongolian gerbil by examining growth and recovery process of TTS by means of CM. Five awake gerbils, aged 4-6 months, were used as subjects in order to avoid the influence of anesthesia. Each gerbil was implanted a chlorinated silver-wire electrode close to the round window to record CM. Animals were comfortably held with harness in a sound attenuated Faraday cage. A loudspeaker was placed at distance of 10 cm from the right ear. For calibrating frequency characteristics of stimuli, a microphone was set at the position of the gerbil to achieve the frequency characteristics of ±2dB between 0.1 and 50 kHz. The exposure was made with 1/3 octave band noise (center frequency 7 kHz) with overall intensity of 80 dB SPL for 20 min. However, the intensity and time for exposure were adjusted to produce appropriate magnitude of TTS. The sounds stimuli for CM recordings were tone bursts of 5-12 kHz with 0.5 kHz steps and duration of 500 ms. We also used linearly frequency modulated (FM) sounds (both upward and downward) with sweeping rage of 0.4-30 kHz and duration of 5 s. Intensities used were 38, 44, 50 dB SPL. The CM was recorded before and after noise exposure to quantify noise-induced damage. After noise exposure, CM was measured with a set of sound stimuli. It took 5 min for each stimulus and 1.5 h for a set. As a result, the maximum noise-damage was observed later than just after noise exposure, which was similar to humans. Time course of TTS process will be discussed by analyzing reduction and recovering of CM to tone bursts of different frequencies. Spectrotemporal signal processing of species-specific vocalized sounds on the basilar membrane will be also discussed. The results shed a light upon structural functions of inner ear in Mongolian gerbils through noise induced hearing loss. Keywords: Auditory Fatigue, Basilar membrane motion, Cochlear nonlinearity, Hair cells, Temporary Threshold Shifts Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for student poster award) Topic: Sensory: Audition Citation: Boku S, Fukushima K, Kobayasi KI, Simmons AM, Simmons JA and Riquimaroux H (2012). Development and recovery process of noise-induced inner ear damage evaluated by cochlear microhonics in Mongolian gerbils, Meriones unguiculatus. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00007 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Prof. Hiroshi Riquimaroux, Graduate School of Life and Medical Sciences, Doshisha University, Department of Biomedical Engineering and Biomedical Information, Graduate School of Life and Medical Sciences, Kyotanabe, Kyoto, 610-0321, Japan, hrikimar@mail.doshisha.ac.jp Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Shokei Boku Keizo Fukushima Kohta I Kobayasi Andrea M Simmons James A Simmons Hiroshi Riquimaroux Google Shokei Boku Keizo Fukushima Kohta I Kobayasi Andrea M Simmons James A Simmons Hiroshi Riquimaroux Google Scholar Shokei Boku Keizo Fukushima Kohta I Kobayasi Andrea M Simmons James A Simmons Hiroshi Riquimaroux PubMed Shokei Boku Keizo Fukushima Kohta I Kobayasi Andrea M Simmons James A Simmons Hiroshi Riquimaroux Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.