Influence of discretization error on instability of cochlear model

Area of Science:

• Auditory Neuroscience
• Computational Acoustics
• Biophysics

Background:

• Hearing relies on the cochlea's active processing, primarily driven by outer hair cells (OHCs).
• Spatially irregular OHC activity impairs cochlear processing and causes excessive instability in current models.
• Two hypotheses explain this instability: inherent model necessity or numerical discretization errors.

Purpose of the Study:

• Investigate the source of excessive instability in cochlear models with irregular OHC activity.
• Determine if instability is an essential feature or a numerical artifact.

Main Methods:

• Developed a state-space model for two-dimensional cochlear mechanics.
• Employed a high-accuracy numerical calculation scheme for simulations.

Main Results:

• Simulations revealed discretization errors dependent on modeling accuracy.
• Increased modeling accuracy led to greater instability, linked to OHC feedback gain irregularity.
• Discretization errors were found to weaken the observed instability.

Conclusions:

• Excessive instability is an essential characteristic of the cochlear model, not solely a result of numerical errors.
• The findings underscore the importance of accurate modeling for understanding cochlear mechanics and hearing.
• Irregular OHC activity's impact on cochlear instability is better understood through these simulations.