# Chaotic Dynamics of Inner Ear Hair Cells

## TL;DR

This paper demonstrates that inner ear hair cells exhibit low-dimensional chaotic dynamics, which may enhance their sensitivity to weak stimuli and aid in sound detection.

## Contribution

It provides experimental evidence of chaos in hair cell dynamics and links it to improved signal detection capabilities.

## Key findings

- Hair cells exhibit low-dimensional chaotic attractors.
- Transition from chaos to order affects signal processing.
- Chaotic regime enhances sensitivity to weak stimuli.

## Abstract

Experimental records of active bundle motility are used to demonstrate the presence of a low-dimensional chaotic attractor in hair cell dynamics. Dimensionality tests from dynamic systems theory are applied to estimate the number of independent variables sufficient for modeling the hair cell response. Poincare maps are constructed to observe a quasiperiodic transition from chaos to order with increasing amplitudes of mechanical forcing. The onset of this transition is accompanied by a reduction of Kolmogorov entropy in the system and an increase in mutual information between the stimulus and the hair bundle, indicative of signal detection. A simple theoretical model is used to describe the observed chaotic dynamics. The model exhibits an enhancement of sensitivity to weak stimuli when the system is poised in the chaotic regime. We propose that chaos may play a role in the hair cell's ability to detect low-amplitude sounds.