Effect of sub-tectorial space fluid dynamics on cochlear energy dissipation and inner hair cell mechano-transduction

In the mammalian cochlea, the mechano-transduction of the inner hair cell (IHC) stereocilia occurs in a micrometer-thick fluid space between the tectorial membrane and the reticular lamina. Using a computational model of the cochlea, we analyzed how the sub-tectorial space (STS) fluid mechanics affect cochlear power dissipation and IHC mechano-transduction. Based on the simulations of a single IHC stereociliary bundle in the STS (Prodanovic et al., 2015), the fluid-induced forces of the STS were reduced to simple equations. The reduced STS response was combined with a whole cochlear model consisting of: organ of Corti structural mechanics, cochlear fluid dynamics, and outer hair cell electro-physiology. Energy dissipation in the cochlea was quantified for three categories: macro-fluidic dissipation along the cochlear scalae, micro-fluidic dissipation in the STS, and other dissipation in the organ of Corti. The phase of IHC mechano-transduction current with respect to the basilar membrane displacement was ...