Active avoidance learning in zebrafish (Danio rerio)--the role of sensory modality and inter-stimulus interval.

The zebrafish (Danio rerio) promises to meet the growing need of a high throughput model in the fields of gerontological and neurobehavioral research by possessing highly conserved anatomy and physiology with vertebrates, while having low maintenance costs. Here we further explore the conditions of active avoidance learning in zebrafish. Two pairs of distinct aversive conditioning experiments using shuttle boxes were designed to compare the effects of sensory modality and conditioned-unconditioned stimulus interval (CS-US interval) upon memory formation and retention. We found that olfactory conditioning with phenylethyl alcohol as a CS was significantly more likely to produce a successful outcome than with a visual CS. Likewise a 10 s CS-US interval yielded significantly more successful memory formation than a 15 s interval. These conditions may further facilitate the use of zebrafish to explore the genetic and neuronal base of active avoidance learning and its neuropharmacological improvement.