Abstract

The optokinetic reflex is a closed-loop gaze-stabilizing ocular motor reaction that minimizes residual retinal image slip during vestibulo-ocular reflexes. In experimental isolation, the reflex is usually activated by motion of an achromatic large-field visual background with strong influence of radiance contrast on visual motion estimation and behavioral performance. The presence of color in natural environments, however, suggests that chromatic cues of visual scenes provide additional parameters for image motion detection. Here, we employed Xenopus laevis tadpoles to study the influence of color cues on the performance of the optokinetic reflex and multi-unit optic nerve discharge during motion of a large-field visual scene. Even though the amplitude of the optokinetic reflex decreases with smaller radiance contrast, considerable residual eye movements persist at the ‘point of equiluminance’ of the colored stimuli. Given the color motion preferences of individual optic nerve fibers, the underlying computation potentially originates in retinal circuits. Differential retinal ganglion cell projections and associated ocular motor signal transformation might further reinforce the color dependency in conceptual correspondence with head/body optomotor signaling. Optokinetic reflex performance under natural light conditions is accordingly influenced by radiance contrast as well as by the color composition of the moving visual scene.

Highlights

  • The optokinetic reflex is a closed-loop gaze-stabilizing ocular motor reaction that minimizes residual retinal image slip during vestibulo-ocular reflexes

  • The optokinetic reflex of Xenopus laevis tadpoles is systematically influenced by the color component of the moving visual scene

  • Even though eye movement amplitudes decrease with smaller radiance contrast, a residual optokinetic response at the point of equiluminance remains, even when accounting for inter-individual variance in the exact location of the POE

Read more

Summary

Introduction

The optokinetic reflex is a closed-loop gaze-stabilizing ocular motor reaction that minimizes residual retinal image slip during vestibulo-ocular reflexes. Gaze-stabilization largely depends on the concerted action of synergistic vestibulo-ocular (VOR) and optokinetic reflexes (OKR)[1] The latter reflex is elicited by large-field visual field motion, operates under closed-loop conditions and ensures minimization of the residual image slip that remains uncompensated by the open-loop ­VOR1–3. Measurements of ocular motor performance under different conditions confirmed a non-zero ocular motor response at iso-luminance and recordings of RGC activity revealed distinct preferences for individual colors of the visual motion stimulus. Part of these results found entry into the thesis of C­ MG24

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call