A flexible anatomical set of mechanical models for the organ of Corti

TL;DR

This paper presents a modular, flexible mechanical model of the organ of Corti that simulates how its components interact to convert basilar membrane vibrations into inner hair cell oscillations, highlighting the importance of component interactions.

Contribution

The authors developed a modular, anatomically detailed mechanical model of the organ of Corti that incorporates nonlinear responses and fluid coupling, enabling detailed study of its mechanical transduction process.

Findings

Slight bending of outer hair cells significantly affects motion transmission.

Components can cooperate to improve frequency selectivity and signal-to-noise ratio.

Model demonstrates the impact of mechanical parameters on inner hair cell motion.

Abstract

We built a flexible platform to study the mechanical operation of the organ of Corti (OoC) in the transduction of basilar membrane (BM) vibrations to oscillations of an inner hair cell bundle (IHB). The anatomical components that we consider are the outer hair cells (OHCs), the outer hair cell bundles, Deiters cells, Hensen cells, the IHB and various sections of the reticular lamina. In each of the components we apply Newton's equations of motion. The components are coupled to each other and are further coupled to the endolymph fluid motion in the subtectorial gap. This allows us to obtain the forces acting on the IHB, and thus study its motion as a function of the parameters of the different components. Some of the components include a nonlinear mechanical response. We found that slight bending of the apical ends of the OHCs can have a significant impact on the passage of motion from the BM to the IHB, including critical oscillator behaviour. In particular, our model implies that the components of the OoC could cooperate to enhance frequency selectivity, amplitude compression and signal to noise ratio in the passage from the BM to the IHB. Since the model is modular, it is easy to modify the assumptions and parameters for each component.