The bullfrog sacculus contains mechanically sensitive hair cells whose stereociliary bundles oscillate spontaneously when decoupled from the overlying membrane. Steady-state offsets on the resting position of a hair bundle can suppress or modulate this native motility. To probe the dynamics of spontaneous oscillation in the proximity of the critical point, we describe here a method for mechanical actuation that avoids loading the bundles or contributing to the viscous drag. Magnetite beads were attached to the tips of the stereocilia, and a magnetic probe was used to impose deflections. This technique allowed us to observe the transition from multi-mode to single-mode state in freely oscillating bundles, as well as the crossover from the oscillatory to the quiescent state.
Bibliographical noteFunding Information:
D.B. was supported in part by NSF Grant No. IOS-0920696 and by NIH Grant No. 1R01DC011380-01A1. J.C. was supported by Creative Research Initiative (2010-0018286), WCU (R32-2009-10217), BK21 Project, and AOARD (FA2386-10-1-4117).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)