Quantifying the Ontogeny of Optokinetic and Vestibuloocular Behaviors in Zebrafish, Medaka, and Goldfish

1 Department of Physiology and Neuroscience, New York University School of Medicine, New York, New York 10016; and 2 Departments of Physics and Molecular Biology, Princeton University, Princeton, New Jersey 08544 Submitted 29 March 2004; accepted in final form 20 July 2004 We quantitatively studied the ontogeny of oculomotor behavior in larval fish as a foundation for studies linking oculomotor structure and function with genetics. Horizontal optokinetic and vestibuloocular reflexes (OKR and VOR, respectively) were measured in three different species (goldfish, zebrafish, and medaka) during the first month after hatching. For all sizes of medaka, and most zebrafish, Bode plots of OKR (0.065–3.0 Hz, ±10°/s) revealed that eye velocity closely followed stimulus velocity (gain > 0.8) at low frequency but dropped sharply above 1 Hz (gain < 0.3 at 3 Hz). Goldfish showed increased gain proportional to size across frequencies. Linearity testing with steps and sinusoids showed excellent visual performance (gain > 0.8) in medaka almost from hatching; but zebrafish and goldfish exhibited progressive improvement, with only the largest equaling medaka performance. Monocular visual stimulation in zebrafish and goldfish produced gains of 0.5 versus