# Active and Nonlinear Models for Cochlear Mechanics

> **NIH NIH R01** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2024 · $552,002

## Abstract

PROJECT SUMMARY:
Rotation of the hair bundles (HB) of the inner hair cells (IHC) of the cochlea open the mechano-electric transducer
(MET) channels of the IHCs. The resulting current depolarizes the cell body inducing neurotransmitter release
and, ultimately, auditory nerve stimulation. The active machinery of the cochlea, driven by motility of outer hair
cells (OHC), both tunes the excitation of the IHC HBs and provides for nonlinear compression. The first specific
aim of the grant involves the quantification of cochlear vibrations when no sound is presented, to characterize
noise floor and test the theory of the cochlear amplifier. The second aim is to predict the cochlear response to
simple and complex acoustic signals and to determine the effect of attachment of IHC mechanically to the
tectorial membrane. Particular emphasis is placed on testing rate-dependent effects in MET models (including
adaptation) and in OHC electromechanics. The specific aims of this grant are to develop mathematical models
of these phenomenon, to rigorously test these hypotheses via comparison to existing experiments, and to work
with our collaborators to devise feasible new experiments to test our predictions.
The overarching goal of this research is to develop a complete fluid-mechanical-electrical model that describes
the response of the cochlea to both external acoustic stimulation. If successful, this model will enhance our
understanding of failure mechanisms in the cochlea, answering important questions as to the morphological
elements of the cochlea that fail and why. Such understanding will improve noninvasive diagnosis of hearing as
abnormalities in the response can be linked to specific pathologies. Finally, having an understanding of how the
cochlea process sound over the entire spectrum will help us to understand how important classes of signals are
processed in the cochlea (such as speech and music) and such understanding can lead to better speech
processing algorithms or cochlear implant electrical stimulation approaches.

## Key facts

- **NIH application ID:** 10905440
- **Project number:** 2R01DC004084-21A1
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Karl Grosh
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $552,002
- **Award type:** 2
- **Project period:** 1999-05-01 → 2029-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10905440

## Citation

> US National Institutes of Health, RePORTER application 10905440, Active and Nonlinear Models for Cochlear Mechanics (2R01DC004084-21A1). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10905440. Licensed CC0.

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