Recording from Sensory Cells in the Statocyst of Astacus

Summary

In the statocyst of Astacus leptodactylus two sets of sensory hairs on the ventral floor were compared with regard to the directionality of their receptor responses: the crescent-shaped hair group in the middle region of the cyst (crescent group) and the transversally arranged single row of hairs in the posterior region of the statocyst (transverse group). Whereas all transverse-group hairs are morphologically polarized to the posterior, the crescent-group hairs are polarized mainly to the anterior, to the medial and to the posterior — depending on their location within the crescent. Deflection of transverse-group hairs to the posterior as well as deflection of many crescent-group hairs to the medial caused a distinct and long-lasting tonic discharge in the statocyst nerve. It was shown that different tilts during circular rotation of the statocyst about its roll axis can be well discriminated by responses of many crescent-group receptors. In contrast, a similar discrimination of tilts about the pitch axis could be achieved only by responses of transverse-group cells.