A vibration-sensitive descending statocyst interneurone in the crayfish Procambarus Clarkii

Abstract

ABSTRACT An interneurone specifically sensitive to substratum vibration was identified in the crayfish circumoesophageal connective. The interneurone, called B1 in this paper, received excitatory input from the statocysts on both sides. Electrical stimulation of the statocyst nerve elicited several spikes in the interneurone with latencies that depended on which side was stimulated. B1 responded phasically to artificial bending of the statocyst sensory hairs. The response was similar to that of the phasic-type receptor in the statocyst. The morphology of B1 was studied by an intracellular staining technique using nickel chloride and subsequent silver intensification. The interneurone projects its neurite arborization to the dorsal part of the deutocerebrum and parolfactory lobe on both sides, where the statocyst primary afferents also project. The overlapping of central projections, together with the properties of the response of B1; suggests that the interneurone receives excitatory input from the phasic-type receptors and transmits information about phasic body movement, but not static positional information, to the posterior ganglia. Branches of B1 also project to the antennal and tegumentary lobes ipsilateral to the axon. B1 may receive additional mechanosensory information from the cuticular sensory hairs on the antennae and the cephalic body surface.