|ZFIN ID: ZDB-PUB-030527-18|
Visuomotor behaviors in larval zebrafish after GFP-guided laser ablation of the optic tectum
Roeser, T. and Baier, H.
|Source:||The Journal of neuroscience : the official journal of the Society for Neuroscience 23(9): 3726-3734 (Journal)|
|Registered Authors:||Baier, Herwig, Roeser, Tobias|
|Keywords:||visual system, vision, retina, optomotor, optokinetic, behavior, retinal ganglion cell, tectum, superior colliculus, zebrafish, Danio rerio, transgenic, GFP, sonic hedgehog, laser ablation|
Roeser, T. and Baier, H. (2003) Visuomotor behaviors in larval zebrafish after GFP-guided laser ablation of the optic tectum. The Journal of neuroscience : the official journal of the Society for Neuroscience. 23(9):3726-3734.
ABSTRACTThe optic tectum is the largest visual center in most vertebrates and the main target for retinal ganglion cells (RGCs) conveying visual information from the eye to the brain. The retinotectal projection has served as an important model in many areas of developmental neuroscience. However, knowledge of the function of the tectum is limited. We began to address this issue using laser ablations and subsequent behavioral testing in zebrafish. We used a transgenic zebrafish line that expresses green-fluorescent protein in RGCs projecting to the tectum. By aiming a laser beam at the labeled retinal fibers demarcating the tectal neuropil, the larval tectum could be selectively destroyed. We tested whether tectum-ablated zebrafish larvae, when presented with large-field movements in their surroundings, displayed optokinetic responses (OKR) or optomotor responses (OMR), two distinct visuomotor behaviors that compensate for self-motion. Neither OKR nor OMR were found to be dependent on intact retinotectal connections. Also, visual acuity remained unaffected. Tectum ablation, however, slowed down the OKR by reducing the frequency of saccades but left tracking velocity, gain, and saccade amplitude unaffected. Removal of the tectum had no effect on the processing of second-order motion, to which zebrafish show both OKR and OMR, suggesting that the tectum is not an integral part of the circuit that extracts higher-order cues in the motion pathway.