SENSORY PRECONDITIONING IN THE TERRESTRIAL MOLLUSK, LIMAX-FLAVUS

Sensory preconditioning (SPC) in the terrestrial slug, Limax flavus, was studied with carrot odor and cucumber odor as the conditioned stimuli (CSs) and quinidine sulfate solution as the unconditioned stimulus (US). When slugs experienced CS1-CS2 and CS2-US training pairs, their odor preference for CS1 was reduced as well as that for CS2. The reduction in CS1 odor preference was observable only when slugs experienced both training pairs. In the second experiment, in order to study the stimulus-stimulus associations after SPC, the conditioned slugs were cooled immediately after presentation of CS1 or CS2. As a result, both odor preferences increased after both CS1+cooling and CS2+ cooling treatments, which suggested that CS1-CS2 and CS2-US associations were formed after SPC. From these results, it is concluded that Limax shows sensory preconditioning and that its stimulus-stimulus associations are similar to those of mammals.