Assessment of Thigmotaxis in Larval Zebrafish

One of the most commonly used behavioral endpoints measured in preclinical studies employing rodent models is thigmotaxis (or “wall-hugging”). Thigmotaxis is the propensity to avoid the center of an arena and stay or move in close proximity to the boundaries of the environment. Thigmotaxis is a validated index of anxiety. While assays measuring thigmotaxis in adult zebrafish have been developed, such assays have not yet been validated in larval zebrafish. Here we present a simple protocol for the measurement of thigmotaxis in zebrafish larvae that is triggered by a sudden change in illumination and performed in a standard 24-well plate. We show that larval zebrafish as young as 5 dpf respond to this challenge by engaging in thigmotaxis. This behavior is sensitive to commonly used anxiolytic (diazepam) and anxiogenic (caffeine) drugs, thus representing the first validated thigmotaxis assay for larval zebrafish. In sum, this protocol is cost-effective, rapid (only 10 min), and amenable to medium- to high-throughput capacity while constituting a valuable tool for stress and central nervous system research as well as for preclinical drug screening and discovery.