What can be learned from a fish: An analysis of visual discrimination in the zebrafish, Danio rerio

In recent years, the zebrafish has become a popular model for the study of developmental biology and genetic analysis. Zebrafish were used in order to demonstrate their ability to discriminate between visual stimuli such as colors, patterns, and colored patterns by using an associative learning paradigm.; Fish were trained to choose between various stimuli in order to receive a food reward. Only fish that responded correctly received a reward. Between trials, the fish were tested with "blanks," where the doors were opened, but there was no stimulus and no reward given. The purpose of this was to track the random movement of the fish. One session consisted of ten trials and ten blanks.; The results have produced many insights into learning in zebrafish. Zebrafish are able to discriminate between certain colors which were tested such as blue and yellow, yellow and orange, and blue and green (p < 0.001), but not blue and aqua (p = 0.9595). Zebrafish are able to discriminate between horizontal and vertical lines (p = 0.002) and are also able to discriminate between sloped lines and horizontal stimuli (p < 0.001) which differ in orientation by ten degrees. Zebrafish attend to patterns more closely than to colors when they are presented simultaneously. Individual fish have their own distinct ability to learn a particular task that is not based on social factors within the group while *AB and pearl danios learn more efficiently than stock zebrafish. Preliminary studies with a tetramethylrhodamine-conantokin-G probe (an NMDA antagonist) revealed different staining patterns in the tecta of learners vs. non-learners.; This work has demonstrated the ability of the zebrafish to learn using an associative learning paradigm. This system may be used as a behavioral screen for visual and/or learning mutants. A possible mechanism for learning has been postulated based on these findings, and the zebrafish may thus be able to serve as a model system for vertebrate learning and memory.