A competition framework for fixation-preference in strabismus

Frontiers in Neuroscience

Neuroscience

Santoshi Ramachandran¹  Vallabh E. Das² 

[1] College of Optometry, University of Houston, Houston, TX, United States;null;

关键词: strabismus;    localization;    superior colliculus;    suppression;    saccade;    exotropia;    nonhuman primates;   

DOI  :  10.3389/fnins.2023.1266387

 received in 2023-07-24, accepted in 2023-09-26,  发布年份 2023

来源: Frontiers

【 摘 要 】

Strabismic subjects often develop the ability to fixate on a target with either eye. Previous studies have shown that fixation-preference behavior varies systematically depending on spatial location of the target. We hypothesized that, when an eccentric target is presented, oculomotor fixation-preference in strabismus may be accounted for in a competitive decision framework wherein the brain must choose between two possible retinal errors to prepare a conjugate saccade that results in one of the eyes acquiring the eccentric target. We tested this framework by recording from visuo-motor neurons in the superior colliculus (SC) of two strabismic rhesus macaque monkeys as they performed a delayed saccade task under binocular viewing conditions. In one experiment, visual targets were presented at one of two locations corresponding to the neuronal receptive field location with respect to either the viewing or the deviated eye. Robust visual sensory responses were observed when targets were presented at either location indicating the presence of competing sensory signals for eye-choice. In a second experiment, a single visual target was placed at the neuronal receptive field location where the animal switched fixation on some trials and did not on other trials. At such target locations where either eye could acquire the target, both visual and build-up activity was greater in trials when the saccade encoded by the neuron “won.” These findings provide evidence for the influence of visual suppression within SC sensory activity and support the possible utilization of a competition framework, one that has been previously described for when a binocularly aligned animal chooses from among multiple targets, to drive fixation-preference behavior in strabismus.

【 授权许可】

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Copyright © 2023 Ramachandran and Das.