Fig. 5.

The twitch’s dependence on hair bundle displacement, as determined by application of variable-amplitude displacement pulses to the base of a stimulus fiber. A, This bundle’s superimposed responses showed that the twitch grew in amplitude with increasing bundle displacement for values up to ∼40 nm; for greater bundle displacements, the twitch’s amplitude progressively declined to zero. B, The twitch’s amplitude is plotted as a function of hair bundle displacement. InA, 14 step displacements, each 400 msec in duration, were delivered to the fiber’s base; the steps were uniformly spaced between and included −400 and 400 nm. An additional record was obtained in the absence of a displacement. The results from 10 stimulus wave trains were averaged; averaged responses of <1 nm, which did not significantly exceed the noise level, are plotted as zero. The data inB were obtained from the same hair bundle by three repetitions of the procedure used to obtain A. The fiber’s stiffness was 293 μN · m⁻¹.