SIGNIFICANCE OF CANAL-RECEPTOR PROPERTIES FOR THE INDUCTION OF PHASE AND GAIN IN THE FLUID-FILLED BALANCE ORGANS OF THE CRAB SCYLLA-SERRATA

1. Properties of the receptors of single sensory hairs (thread hairs) were studied electrophysiologically in the isolated, opened, canals of the statocyst of the crab, Scylla serrata. 2. Each thread hair is innervated by two receptors which have an opposite directional sensitivity to hair displacements. Most receptors are phasic-tonic, some are purely phasic (Fig. 5). The phasic-tonic receptors have a bell shaped stimulus-response curve (Figs. 6 and 7). 3. The thread hairs can deflect over a wide range. Over parts of this range the receptors are sensitive to displacement, over other parts they are sensitive to velocity (Fig. 8). 4. The effect of gravity on the thread hairs was measured (Fig. 9) and the relationship between the pitch position of the crab and the position of the thread hairs relative to the sensory cushion was calculated (Fig. 11). Taken together with the effect of the hair position on the receptor sensitivity we could infer the phase and gain of the thread-hair receptor output in different pitch positions of the crab (Fig. 12). 5. On the basis of the inferred effects of the position of the crab on the receptor output we could predict particular fluctuations in phase and gain in the eye reflex if the crab were oscillated in different pitch positions. These predictions match with the results of previous behavioral experiments. 6. The properties of the canal receptors of the crab are essentially similar to those of vertebrates. © 1979 Springer-Verlag.