# Cochlear mechanics in the mouse

> **NIH NIH R01** · UNIVERSITY OF SOUTHERN CALIFORNIA · 2020 · $637,608

## Abstract

Project Summary/Abstract
Sound pressure produces force across the mammalian cochlear partition, ultimately creating a vibratory
traveling wave that propagates longitudinally up the cochlear duct. The key feature distinguishing this process
from the non-mammalian cochlea is amplification, whereby forces produced by thousands of outer hair cells
(OHCs) sharpen and amplify the traveling wave. Our overarching objective is to understand how the complex
biomechanics of the 3D multi-cellular and acellular arrangement that form the organ of Corti work together to
create cochlear amplification. Specifically, we will determine how this process, which stems from the broadly-
tuned basilar membrane, creates sharp frequency tuning and high sensitivity. This question is significant on a
basic science level because these biophysical processes underlie the ability to hear sounds just above the
Brownian motion of molecules in air with an exquisite frequency resolution. This question remains unsolved
and is clinically important because hearing loss is typically due to loss of cochlear amplification. Our central
hypothesis is that, beyond the broad tuning provided by basilar membrane mechanics, the forces produced by
OHCs are also tuned by additional mechanisms. In aim 1, we will use 3D Volumetric Optical Coherence
Tomography and Vibrometry (VOCTV) in mice to test whether the forces produced by OHCs are tuned by the
mechanics of the supporting cells and acellular structures that form the organ of Corti. In aim 2, we will use 1D
VOCTV in awake behaving mice to test whether cochlear amplification is modulated by brain state via the
medial olivocochlear efferent (MOC) system by varying OHC force production. Together, these data will be
interpreted so as to test our hypothesis. If our hypothesis is true, sharply-tuned differential motion within the
organ of Corti is necessary to generate the sensitivity and sharp tuning of the mammalian cochlea and brain
state modulates cochlear amplification via the MOC efferent system.

## Key facts

- **NIH application ID:** 9967475
- **Project number:** 2R01DC014450-07
- **Recipient organization:** UNIVERSITY OF SOUTHERN CALIFORNIA
- **Principal Investigator:** John S Oghalai
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $637,608
- **Award type:** 2
- **Project period:** 2015-05-01 → 2025-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9967475

## Citation

> US National Institutes of Health, RePORTER application 9967475, Cochlear mechanics in the mouse (2R01DC014450-07). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9967475. Licensed CC0.

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