MECHANOPHYSIOLOGICAL PROPERTIES OF THE SUPRAORBITAL LATERAL-LINE CANAL IN RUFFE (ACERINA-CERNUA L)

In vivo measurements of the motion of the skin covering the supraorbit al lateral line canal of the ruffe are presented. Stimulation of the l ateral line with local oscillatory water motion evokes displacement of the skin which exhibits a characteristic node-antinode pattern along the length of the canal. Frequency responses of the skin show tuning w ith resonance frequencies comparable with the 'best frequencies' of th e cupula, suggesting that cupular dynamics is involved in the generati on of the node-antinode pattern. Indeed, the experiments show that the node-antinode pattern is caused by the presence of the cupulae in the canal. A hydrodynamic model describing the dynamics of the skin is pr esented. The model accounts for many of the observed phenomena, and le ads to the conclusion that the motion of the skin reflects the microme chanical properties of the sensory bundles of the hair cells underlyin g the cupula.