Computer-based analysis of the optokinetic response in zebrafish larvae

INTRODUCTIONLarge movements in the visual field trigger stereotypic eye movements in vertebrates. This optokinetic response (OKR) is robust in zebrafish (Danio rerio) larvae older than 4 days post-fertilization (dpf), and is hence ideally suited for use in the evaluation of visual performance after genetic manipulations. This protocol describes a simple method by which a computer-generated visual stimulus is projected onto a screen and watched by immobilized larvae. The resulting eye movements are recorded and evaluated automatically, using a digital video camera and appropriate computer software. Depending on the sophistication of the software used, the evaluation can be performed in real time during the recording session, or by analyzing the recorded movie files off-line.