Evolutionary conservation, translational relevance and cognitive function: The future of zebrafish in behavioral neuroscience.

The zebrafish is becoming increasingly well utilized in several fields of biology, including behavioral neuroscience. This review, based upon an Outstanding Achievement Award lecture presented by the author at an IBNS conference, explores the potential reasons for the popularity of this species. First, some theoretical questions are discussed, including why a comparative approach using more than a single laboratory animal species (the mouse) may be important. Points about evolutionary conservation are considered. Discussion on why complexity may build over time, and what it means when a species is considered "primitive" vs "advanced", are also included. Arguments about how using a "primitive" species may work to the researcher's advantage are made in the context of translational relevance. Most discussions center around a complex functional aspect of the brain, relational learning and memory, and use empirical examples from the author's own laboratory. It is hoped that these examples will show how a simple vertebrate, like the zebrafish, may help the investigator address fundamental mechanistic questions about complex brain function and behavior.