와우증폭기의 비밀 |
최철희 |
대구가톨릭대학교 바이오메디대학 언어청각치료학과, 생체모방감각제어연구소, 가톨릭 청각음성언어센터 |
The Mystery of a Cochlear Amplifier |
Chul-Hee Choi |
Department of Audiology and Speech-Language Pathology, Research Institute of Biomimetic Sensory Control, and Catholic Hearing Voice Speech Center, Catholic University of Daegu, Gyeongsan, Korea |
Correspondence |
Chul-Hee Choi ,Tel: +82-53-850-2541, Fax: +82-53-359-0780, Email: cchoi@cu.ac.kr
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Received: March 2, 2016; Accepted: March 10, 2016. Published online: March 31, 2016. |
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ABSTRACT |
The presence of a cochlear amplifier is required for a dramatic improvement of hearing sensitivity and frequency selectivity in normal
hearing of mammals. The cochlear amplifier refers to the active process of the cochlea maximizing the gain in response to low levels of
input signals and minimizing the gain at their high levels as an automatic gain control. The cochlear amplifier is involved in two gain or
transfer functions of hair cells or outer hair cells in the cochlea: mechano-electrical transduction (MET) and electro-mechanical transduction
(EMT). The mechano-eletcrical transduction located within the stereocilia on the apex of the OHCs indicates a nonlinear transducer
function opening the transducer channels through deflection of hair cell bundle into the tallest stereocilia and entering the K+ and Ca2+
into the cells which increases the hair cell receptor potentials, called depolarization and closing the channels through the deflection in
the opposite direction and outflowing the K+ and Ca2+ out of the cells which decreases the hair cell receptor potentials, called hyperpolarization.
The electro-mechanical transduction placed in the lateral wall of the OHCs represents the changes in the length and form of isolated
OHC in response to the changes of OHC receptor potentials in mammals. This paper reviews the basic mechanisms and the new
discovery of the cochlear amplifier, the new methods to characterize the presence, and the clinical approaches to expose the mystery. |
Key Words:
Cochlear amplifier, Mechano-eletcrical transduction, Electro-mechanical transduction, Electromotility, Outer hair cell. |
중심단어:
와우증폭기· 기계-전기적 변환· 전기-기계적 변환· 전기적 운동· 외유모세포. |
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