S1-2.7 Jan. 4 Sensing moving fluid: Hydroreception in the lateral line system of zebrafish MCHENRY, M.J.*; STROTHER, J.A.; VAN TRUMP, W.J.; NETTEN, VAN, S.M.; U.C. Irvine; U.C. Irvine; U.C. Irvine; Univ. of Groningen, NL firstname.lastname@example.org
Fish sense water flow with numerous microscopic structures on the surface of their skin. These structures, known as superficial neuromasts (SNs), are part of the lateral line system, which provides sensory cues that influence rheotaxis, schooling, mating, and predator-prey interactions. Despite the importance of these cues to the sensory ecology of fish, it is unclear how the mechanics of SNs influence the transduction of hydrodynamic signals. We examined the mechanics of hydroreception in SNs with a combination of quasi-static stiffness measurements, morphometrics, and computational modeling in zebrafish larvae (Danio rerio). Our results suggest that the boundary layer at the body's surface behaves as a filter that significantly attenuates and phase shifts stimuli. Signals are further filtered by the SN in a manner that depends on its stiffness and drag coefficient. The kinocilia of hair cells at the base of the SN function to stiffen the structure and the surrounding compliant matrix generates drag. This drag causes deflections in the kinocilia that generate graded potentials in the hair cell bodies. The results of our computational modeling suggests that the observed mean dimensions of SNs (~40 microns tall, ~10 microns in diameter) are close to optimal sensitivity. However, the large morphological variation that we measured among larvae is predicted to result in highly differing filtering characteristics. This suggests that different fish may extract very different information from the same flow field.