Photoresponse from the statocyst hair cell in Lymnaea stagnalis

Sensory cells for associative learning of light and turbulence were studied in Lymnaea. Intracellular recordings with Lucifer Yellow filled electrodes were made from photoreceptors and statocyst hair cells. Photoreceptors had a long latency, graded depolarizing response to a flash of light; they extended their axon to the cerebral ganglion. The caudal hair cell, one of 12 cells in the statocyst, responded to brief light with a depolarization and superimposed impulse activity. It formed its terminal arborization close to the photoreceptor endings in the cerebral ganglion. Ca(2+)-free saline reversibly abolished the photoresponse in the hair cell, suggesting the information was conveyed via a chemical synapse. These findings demonstrated that sensory information for associative learning was convergent at the statocyst hair cell.