Understanding how the nervous system recognizes salient stimuli in the environment and selects and executes the appropriate behavioral responses is a fundamental question in systems neuroscience. To facilitate the neuroethological study of visually guided behavior in larval zebrafish, we developed “virtual reality” assays in which precisely controlled visual cues can be presented to larvae whilst their behavior is automatically monitored using machine vision algorithms. Freely swimming larvae responded to moving stimuli in a size-dependent manner: they directed multiple low amplitude orienting turns (∼20°) toward small moving spots (1°) but reacted to larger spots (10°) with high-amplitude aversive turns (∼60°). The tracking of small spots led us to examine how larvae respond to prey during hunting routines. By analyzing movie sequences of larvae hunting paramecia, we discovered that all prey capture routines commence with eye convergence and larvae maintain their eyes in a highly converged position for the duration of the prey-tracking and capture swim phases. We adapted our virtual reality assay to deliver artificial visual cues to partially restrained larvae and found that small moving spots evoked convergent eye movements and J-turns of the tail, which are defining features of natural hunting. We propose that eye convergence represents the engagement of a predatory mode of behavior in larval fish and serves to increase the region of binocular visual space to enable stereoscopic targeting of prey.
Keywords: zebrafish, prey capture, behavior, binocular vision, ocular vergence
Citation: Bianco IH, Kampff AR and Engert F (2011) Prey capture behavior evoked by simple visual stimuli in larval zebrafish. Front. Syst. Neurosci. 5:101. doi: 10.3389/fnsys.2011.00101
Received: 09 November 2011;
Accepted: 29 November 2011;
Published online: 16 December 2011.
Edited by:Federico Bermudez-Rattoni, Universidad Nacional Autónoma de México, Mexico
Reviewed by:James W. Grau, Texas A&M University, USA
Copyright: © 2011 Bianco, Kampff and Engert. This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
*Correspondence: Isaac H. Bianco, Department of Molecular and Cellular Biology, Harvard University, BioLabs-2073, 16 Divinity Avenue, Cambridge, MA 02138, USA. e-mail: firstname.lastname@example.org