The long term goal of the proposed research is to confirm that outer hair cells are responsible for electromechanical amplification in the cochlear and to clarify the underlying mechanisms of this amplification. The specific goals of the proposal are to determine which properties of the organ of Corti are responsible for the cochlear frequency map, to establish how the OHCs amplify the traveling wave, to determine how the motions of the cochlear partition is coupled to IHC stereocilia motion, and to establish how otacoustic emissions relate to the cochlea partition motion. To achieve these goals, the investigators will measure the mechanical impedance of the cellular and extracellular elements of the organ of Corti, to image the motion of the elements of the organ of Corti in response to electrical and mechanical stimulation in excised cochleas, and to simultaneously measure basilar membrane motion, cochlear microphonics, and otacoustic emissions in live animals. The results of the proposed experiments together with previous experiments by the investigators and others will be interpreted with the aid of computational models. Two types of models will be used: micromechanical and macromechanical. The computational models will be physically based as possible and will include specific descriptions of the mechanical properties of the organ of Corti, basilar membrane, and tectorial membrane, as well as hair-cell mechanoelectric transduction and OHC motility.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
2R01DC000029-08
Application #
2696986
Study Section
Hearing Research Study Section (HAR)
Project Start
1990-04-01
Project End
2003-06-30
Budget Start
1998-07-01
Budget End
1999-06-30
Support Year
8
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Boston University
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118
Zagadou, B F; Barbone, P E; Mountain, D C (2014) Elastic properties of organ of Corti tissues from point-stiffness measurement and inverse analysis. J Biomech 47:1270-7
Zagadou, Brissi Franck; Mountain, David C (2012) Analysis of the cochlear amplifier fluid pump hypothesis. J Assoc Res Otolaryngol 13:185-97
Karavitaki, K Domenica; Mountain, David C (2007) Imaging electrically evoked micromechanical motion within the organ of corti of the excised gerbil cochlea. Biophys J 92:3294-316
Chen, Fangyi; Cohen, Howard I; Bifano, Thomas G et al. (2006) A hydromechanical biomimetic cochlea: experiments and models. J Acoust Soc Am 119:394-405