Static length changes of cochlear outer hair cells can tune low-frequency hearing
Fig 4
Predicted motion of the reticular lamina for different parameter values.
(A) A small value of the Deiter’s cell extensibility Δ leads to a large reticular-lamina displacement. At a critical extensibility ΔC ≈ 1.2 (dashed strip) the displacement vanishes. The critical extensibility ΔC varies slightly with the outer hair cell contraction ϵ. (B) The Deiter’s cell extensibility Δ strongly influences the relation between reticular-lamina displacement (dashed) and Hensen-cell motion (solid) for the model parameter Γ = 0.1 as identified from comparison with experiments. The Hensen-cell motion for the model parameter Δ = 1.15 (red) is in very good qualitative agreement with experimental results of in vitro Hensen cell motion under applied current [20, 34]. Both the motion of the Hensen cells and of the reticular lamina depends nonlinearly on the contraction ϵ of the outer hair cells, and this nonlinearity is particularly pronounced for a Deiter’s cell extensibility Δ close to the critical value ΔC. (C) The nonlinear dependence in the reticular-lamina motion DRL on the contraction of the outer hair cells ϵ implies that the absolute value of the derivative of DRL with respect to the contraction ϵ varies with ϵ. The relative change is particularly strong for a large extensibility Δ of the Deiter’s cells, which has important functional implications.