Reversed Optokinetic Nystagmus (OKN): Mechanism and Clinical Significance

Halmagyi, G. Michael; Gresty, Michael A.; Leech, John

doi:10.1002/ana.410070507

Cited by 71 publications

(39 citation statements)

References 10 publications

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“…This altered behavior is predicted by earlier experiments, which have shown that experimentally induced ipsilateral projections in adult goldfish likewise lead to a reversed OK R (Easter and Schmidt, 1977). Reversed optokinetic nystagmus of genetic origin has also been reported for a congenital human pathology (Halmagyi et al, 1980). We suggest the following interpretation for the reversed OKR.…”

Section: Ipsilateral Projections In Belladonna Lead To Reversed Okrsupporting

confidence: 53%

Genetic Disorders of Vision Revealed by a Behavioral Screen of 400 Essential Loci in Zebrafish

Neuhauss

Biehlmaier

Seeliger³

et al. 1999

J. Neurosci.

383

430

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We examined optokinetic and optomotor responses of 450 zebrafish mutants, which were isolated previously based on defects in organ formation, tissue patterning, pigmentation, axon guidance, or other visible phenotypes. These strains carry single point mutations in Ͼ400 essential loci. We asked which fraction of the mutants develop blindness or other types of impairments specific to the visual system. Twelve mutants failed to respond in either one or both of our assays. Subsequent histological and electroretinographic analysis revealed unique deficits at various stages of the visual pathway, including lens degeneration (bumper), melanin deficiency (sandy), lack of ganglion cells (lakritz), ipsilateral misrouting of axons (belladonna), optic-nerve disorganization ( grumpy and sleepy), inner nuclear layer or outer plexiform layer malfunction (noir, dropje, and possibly steifftier), and disruption of retinotectal impulse activity (macho and blumenkohl). Surprisingly, mutants with abnormally large or small eyes or severe wiring defects frequently exhibit no discernible behavioral deficits. In addition, we identified 13 blind mutants that display outer-retina dystrophy, making this syndrome the single-most common cause of inherited blindness in zebrafish. Our screen showed that a significant fraction (ϳ5%) of the essential loci also participate in visual functions but did not reveal any systematic genetic linkage to particular morphological traits. The mutations uncovered by our behavioral assays provide distinct entry points for the study of visual pathways and set the stage for a genetic dissection of vertebrate vision.

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Section: Ipsilateral Projections In Belladonna Lead To Reversed Okrsupporting

confidence: 53%

Genetic Disorders of Vision Revealed by a Behavioral Screen of 400 Essential Loci in Zebrafish

Neuhauss

Biehlmaier

Seeliger³

et al. 1999

J. Neurosci.

383

430

View full text Add to dashboard Cite

show abstract

“…Interestingly, albinism is a condition that has been associated with altered patterns of retinal ganglion cell (RGC) decussation in the optic chiasm and deficits in eye morphogenesis (Jeffery, 1997). Moreover, reversed OKR has also been observed in normally pigmented humans where it mostly co-occurs with CN (Halmagyi et al, 1980). However, the underlying optic projection was not analyzed in these patients.…”

Section: Introductionmentioning

confidence: 99%

Oculomotor Instabilities in Zebrafish Mutantbelladonna: A Behavioral Model for Congenital Nystagmus Caused by Axonal Misrouting

Huang¹,

Rinner²,

Hedinger³

et al. 2006

J. Neurosci.

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A large fraction of homozygous zebrafish mutant belladonna (bel) larvae display a reversed optokinetic response (OKR) that correlates with failure of the retinal ganglion cells to cross the midline and form the optic chiasm. Some of these achiasmatic mutants display strong spontaneous eye oscillations (SOs) in the absence of motion in the surround. The presentation of a stationary grating was necessary and sufficient to evoke SO. Both OKR reversal and SO depend on vision and are contrast sensitive.We built a quantitative model derived from bel fwd (forward) eye behaviors. To mimic the achiasmatic condition, we reversed the sign of the retinal slip velocity in the model, thereby successfully reproducing both reversed OKR and SO. On the basis of the OKR data, and with the support of the quantitative model, we hypothesize that the reversed OKR and the SO can be completely attributed to RGC misrouting. The strong resemblance between the SO and congenital nystagmus (CN) seen in humans with defective retinotectal projections implies that CN, of so far unknown etiology, may be directly caused by a projection defect.

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“…Gaze-modulated waveforms have also been described such that when the stimulus field is moved right to left, the spdhtaneous nystagmus habitually found on looking to the left is present even though the eyes are directed toward the primary position 12,12).…”

mentioning

confidence: 98%

The influence of preexiting oscillations on the binoculars optokinetic response

Abadi¹,

Dickinson²

1985

Annals of Neurology

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Full-field binocular optokinetic responses were examined in patients with congenital nystagmus. If the stimulus moved in the same plane as the congenital nystagmus, a gaze-modulated response was recorded for both idiopathic and albino observers. When the congenital nystagmus was almost totally suppressed, neither a gaze-evoked nor a sawtooth response was seen. For stimulus movements in a plane orthogonal to the congenital nystagmus, normal sawtooth optokinetic responses were exhibited by both groups. Experimental evidence supports the hypothesis that the optokinetic response in the meridian of the spontaneous oscillation has been adapted.

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Reversed Optokinetic Nystagmus (OKN): Mechanism and Clinical Significance

Cited by 71 publications

References 10 publications

Genetic Disorders of Vision Revealed by a Behavioral Screen of 400 Essential Loci in Zebrafish

Genetic Disorders of Vision Revealed by a Behavioral Screen of 400 Essential Loci in Zebrafish

Oculomotor Instabilities in Zebrafish Mutantbelladonna: A Behavioral Model for Congenital Nystagmus Caused by Axonal Misrouting

The influence of preexiting oscillations on the binoculars optokinetic response

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