Integration of hydrostatic pressure information by identified interneurones in the crab Carcinus maenas (L.); Long-term recordings

Migrating species may utilise hydrostatic pressure. In the aquatic environm ent, hydrostatic pressure changes much more rapidly than in air. In shallow water, tidal changes will impose larger percentage changes on organisms th an those experienced in deep water. Small changes in pressure often cause l ocomotion (barokinesis) accompanied by orientation to light or gravity, oft en partially compensating for the equivalent depth change. Until recently, identification of hydrostatic pressure receptors without a gas phase has pr oved elusive, but it is now known that thread hair receptors in the statocy st of the shore crab Carcinus maenas respond to small changes in hydrostati c pressure. Using a tide machine, the responses of thread hairs to sinusoid ally changing pressure cycles have been examined, and this paper reports pr ogress monitoring this receptor and making long-term recordings from hydros tatic pressure sensitive pathways in the crab's nervous system.