Computer simulation of the mechanical stimulation of the saccular membrane of bullfrog

A three-dimensional computer simulation of the experiment (Benser M. E., Issa N.P., Hudspeth A.J., 1993. Hear. Res. 68, 243-252), devoted to the mechanical stimulation of the surface of saccular membrane of bullfrog with the otoconial mass removed was carried out by finite-element method. Comparison of the calculated distribution of the membrane displacements with the experimental data indicates that the gel layer of the saccular membrane is inhomogeneous. Its lower, thin (6-10 microm) sublayer bordering the macular surface has the smaller Young's modulus which is 20 times less than the modulus of the upper part of the gel membrane (2.5x10(2) N/m(2) and 6.6x10(3) N/m(2), respectively). Possible consequences of this result and modification of the experiment are being discussed. The estimates based on the results of simulation support the conclusion that hair bundle stiffness may dominate the elastic reactance to otolithic membrane shear (Benser et al., 1993).