Neurophysiological Correlates of the Behavioral Response to Light in the Sea Anemone Anthopleura elegantissima.

Neurophysiological responses to light in Anthopleura elegantissima do not involve the ectodermal slow system 1 (SS1). Activities in both the endodermal slow system 2 (SS2) and the through conducting nerve net (TCNN) change when the lighting changes, but the response is not consistent. Thus, photoreception in A. elegantissima probably occurs in the endoderm because SS2 and the TCNN are involved and SS1 is not. We hypothesize either that the photoreception occurs in sensory cells in a local nerve net, with the information then being transmitted to the muscles, or that the muscles themselves are light sensitive. In either case, the TCNN and SS2 become involved after the transduction, and as a consequence--rather than the cause--of muscular activation. The conducting systems of zooxanthellate specimens have a higher frequency of activity than those of apozooxanthellate individuals.