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Spontaneous cellular vibrations in the guinea-pig cochlea
S E Keilson1, S M Khanna, M Ulfendahl
1Department of Applied Physics, Columbia University, New York.
Acta Oto-Laryngologica
|September 1, 1993
Summary
Spontaneous vibrations in Hensen cells were detected using laser interferometry. These vibrations, originating from outer hair cells, may explain spontaneous otoacoustic emissions.
Area of Science:
- Auditory Neuroscience
- Bioacoustics
- Cellular Mechanics
Background:
- Hensen cells play a critical role in auditory transduction.
- Spontaneous otoacoustic emissions (SOAEs) are sounds produced by the ear without external stimulation, but their origin remains debated.
Purpose of the Study:
- To investigate the presence and characteristics of spontaneous mechanical vibrations in Hensen cells.
- To determine the relationship between Hensen cell vibrations and spontaneous otoacoustic emissions.
Main Methods:
- Utilized a laser-heterodyne interferometer to measure mechanical vibrations of Hensen cells in a guinea-pig temporal-bone preparation.
- Employed smoothed periodogram analysis to identify spontaneous spectral components in cell vibrations.
- Determined frequency tuning curves of Hensen cells via external auditory stimulation.
Main Results:
- Detected spontaneous mechanical vibrations in some Hensen cells, appearing as distinct peaks above the noise floor in spectral analysis.
- Observed that the frequencies of these spontaneous vibrations varied between preparations, ruling out ambient noise as a cause.
- Found that spontaneous vibration frequencies generally fell within the principal peak region of the cells' frequency tuning curves.
Conclusions:
- Spontaneous mechanical vibrations in Hensen cells are a measurable phenomenon.
- These vibrations likely originate from outer hair cells.
- The study proposes that these Hensen cell vibrations are the source of spontaneous otoacoustic emissions.