Fig. 8.
Stiff hair bundles have distinctive morphologies. Measured hair bundle stiffness as a function of the 6 morphological features evaluated in this study. The stiffest bundles (kB ≥ 50 μN/m) and the more compliant bundles are indicated by red circles and blue circles, respectively. In the stiffest bundles, the kinocilia are relatively short (A), the tallest stereocilia are tall (B), kinocilia and the tallest stereocilia are approximately the same height (KS ratio approximately equal to 1; C), the shortest stereocilia are often taller than in more compliant bundles (D), array lengths are longer (E), and Slopes are steeper (F). Insets for each plot are box plots that compare summary statistics for stiff (red) and compliant (blue) hair bundle groups. Gray circles, medians; light shading, interquartile range; dark shading, 95% confidence intervals of median; whiskers, 1.5 × interquartile range; isolated points, outliers. Nonoverlapping confidence intervals indicate that differences between the 2 stiffness groups are significant for all 6 structural features. Note that some symbols in D and E overlap the insets.