Inhibitory Avoidance and Color Discrimination Learning in Zebrafish

The unique properties of zebrafish, such as its high reproductive capability, small size, simple genome, and relatively low maintenance cost, make it a cheap and effective genetic model for scientists to study. As a result, scientists have acquired an enormous quantity of zebrafish genetic information and developed numerous genetic tools for the zebrafish. With the large amount of zebrafish information available, one area that is lacking is behavioral characterization and, therefore, effective and reliable behavioral experiment models are lacking as well. After years of research on the zebrafish, our laboratory has discovered successful behavioral models for zebrafish and goldfish in the areas of learning and memory. This chapter discusses two of these models. The first is the Inhibitory Avoidance Experimental Model, and the second is a Color Discrimination Model. In the inhibitory avoidance paradigm, the animals had to learn to avoid an aversive stimulus present on the aquarium preferred compartment. Immediately after training, one group received saline and the other one did not receive the injection. On the test day, the time to cross to the preferred compartment was determined. The latency to enter the black compartment increased significantly on the second trial in relation to BL. No difference between the animal’s latencies on T2, on the test of non-injected animals, or saline-treated animals was recorded, indicating that the animals did not forget the adverse experience from the previous day. The second experiment is a color discrimination model for zebrafish. On each of the 5 consecutive days of experiment (D1, D2, D3, D4, D5), animals had to associate the feeder indicated by the green light with food offering. The latency to enter the feeding area indicated by the green light decreased throughout the trials, with significant difference between D5 and D1 indicating that the animals were able to learn the task. Our results indicate that these tests represent suitable experimental models for the study of learning and memory in zebrafish.