Investigating cochlear responses using a physiologically based model

Thumbnail Image
Files
SAMARAS-DISSERTATION-2025.pdf (10.1 MB)
Author(s)
Samaras, Georgios
Advisor(s)
Editor(s)
Associated Organization(s)
Organizational Unit
Organizational Unit
Series
Collections
Theses and Dissertations
Supplementary to:
Permanent Link
https://hdl.handle.net/1853/77780
Abstract
The mammalian cochlea bestows humans and other mammals with remarkable hearing ability over a wide range of frequencies and stimulus levels. This is achieved in part through an active feedback mechanism, termed the cochlear amplifier, which boosts the cochlear response to low-level stimuli. Cutting edge experiments over the last few decades have probed mechanical and electrical responses inside the cochlea with unprecedented detail. These studies have shown that the organ of Corti, which is a strip of cellular and structural components in the cochlea that mediates sound transduction to nerve signals, exhibits com plex relative motions rather than rigid body motion as previously thought. In turn, these new findings have challenged traditional theories about how the cochlear amplifier, which is facilitated by outer hair cells in the organ of Corti, functions. In this dissertation, a com putational model of the mammalian cochlea is implemented with a reformulated structural model of the organ of Corti that improves the feasibility of changes to model assumptions. The model is used to show that compliance of some structural elements of the organ of Corti leads to complex motion between organ of Corti structures. Furthermore, the Deit ers’ cells in the organ of Corti are made much more compliant than the basilar membrane, based on new evidence. The influence of this more realistic compliance on power transfer to cochlear traveling waves is evaluated. The results of this study challenge the traditional theory of how outer hair cells amplify cochlear responses, which is that they apply a force directly on the basilar membrane through rigid Deiters’ cells, and a new theory of how they may do so is presented. By expanding model assumptions based on experimental evidence, and characterizing power delivery of the cochlear amplifier, the research in this thesis expands understanding of cochlear mechanics.
Sponsor
Date
2025-01-13
Extent
Resource Type
Text
Resource Subtype
Dissertation
Rights Statement
Rights URI