Horizontal and Vertical Optokinetic Eye Movements in Macaque Monkeys with Infantile Strabismus: Directional Bias and Crosstalk
Overview
Authors
Affiliations
Purpose: Optokinetic eye movements stabilize gaze by tracking motion of the visual scene during sustained movement of a creature's body. The purpose of this study was to describe vertical and horizontal optokinetic nystagmus (OKN) in nonhuman primates (NHPs) with normal binocular vision, and to compare their responses to NHPs with binocular maldevelopment induced by prism-rearing.
Methods: Optical strabismus was created in infant macaques (n = 6) by fitting them with prism goggles. The goggles were removed after 3, 6, 9, or 12 weeks to determine the effects of increasing durations of binocular noncorrespondence. Infant NHPs (n = 2) reared wearing plano goggles served as controls. OKN was evoked by horizontal or vertical stripe motion. Eye movements were recorded by using binocular search coils.
Results: NHPs reared in early infancy under conditions of binocular noncorrespondence for durations of 6 weeks or longer had horizontal OKN responses biased directionally in favor of nasalward motion. NHPs reared with prisms for any duration had vertical OKN responses more biased than normal NHPs in favor of upward motion. Diagonal "crosstalk" during horizontal or vertical OKN (vertical slow phases during horizontal stimulus motion, and vice versa) was present to some degree in all NHPs. However, crosstalk-upward during horizontal OKN and nasalward during vertical OKN-was most pronounced in NHPs reared with prism for durations long enough to induce a permanent esotropic strabismus (longer than 3 weeks).
Conclusions: With fusion maldevelopment, the OKN pathways retain a nasalward and upward bias. During forward locomotion, optic flow excites temporalward and downward visual motion in each eye. The OKN biases would act in counterbalance. The biases attenuate with emergence of fusion, but may persist and crosstalk when fusion is impeded.
Liu F, Wang Z, Huang W, Xu Y, Sang X, Liu R Zool Res. 2022; 44(1):153-168.
PMID: 36484227 PMC: 9841183. DOI: 10.24272/j.issn.2095-8137.2022.254.
Childhood Onset Strabismus: A Neurotrophic Factor Hypothesis.
Rudell J, Fleuriet J, Mustari M, McLoon L J Binocul Vis Ocul Motil. 2021; 71(2):35-40.
PMID: 33872122 PMC: 8102408. DOI: 10.1080/2576117X.2021.1893585.
Fleuriet J, Willoughby C, Kueppers R, Mustari M, McLoon L Sci Rep. 2020; 10(1):11927.
PMID: 32681083 PMC: 7368047. DOI: 10.1038/s41598-020-68743-3.
Strabismus and the Oculomotor System: Insights from Macaque Models.
Das V Annu Rev Vis Sci. 2017; 2:37-59.
PMID: 28532347 PMC: 5443124. DOI: 10.1146/annurev-vision-111815-114335.
Joshi A, Agaoglu M, Das V Strabismus. 2017; 25(2):47-55.
PMID: 28463578 PMC: 6015764. DOI: 10.1080/09273972.2017.1317821.