Figure 1.

Probe tip contacts the stereocilia unevenly (simulation). (A) The modeled OHC stereocilia bundle has 29 columns and three rows of stereocilia. Two types of horizontal connectors. Different mechanical properties were assigned for the horizontal connectors along the primary axis (k_HC1 = 10 mN/m) and nonprimary axes (k_HC2 = 1 and 5 mN/m for OHC and IHC, respectively). (B) The modeled IHC stereocilia bundle has 19 columns and three rows of stereocilia. (C) Vertical view of a probe with 3.5-μm radius contacting the OHC stereocilia. (D) It was assumed that the probe contacts the stereocilia at their tips. (E) Sequential plots of probe attachment to the OHC stereocilia. The probe with a spherical tip (r = 3.5 μm) was represented by a rigid beam elements (dark-blue curve). Contact links connect the probe surface and the stereocilia tips (see Materials and Methods for details). As the probe moves from 0 to 1 μm and back to 0 μm, the number of contacting stereocilia (red and green contact links) varies. An established contacting point holds up to 100 pN of tension. (F) Probe attachment to the IHC stereocilia. The IHC probe tip has a greater radius of curvature (r = 15 μm) than the OHC probe to fit well into the IHC stereocilia bundle. The scale bars in hair bundle plots indicate 0.5 μm. To see this figure in color, go online.