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Neurological Basis for Eye Movements of the Blind

When normal subjects fix their eyes upon a stationary target, their gaze is not perfectly still, due to small movements that prevent visual fading. Visual loss is known to cause greater instability of gaze, but reported comparisons with normal subjects using reliable measurement techniques are few....

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Autores principales: Schneider, Rosalyn M., Thurtell, Matthew J., Eisele, Sylvia, Lincoff, Norah, Bala, Elisa, Leigh, R. John
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3575504/
https://www.ncbi.nlm.nih.gov/pubmed/23441203
http://dx.doi.org/10.1371/journal.pone.0056556
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author Schneider, Rosalyn M.
Thurtell, Matthew J.
Eisele, Sylvia
Lincoff, Norah
Bala, Elisa
Leigh, R. John
author_facet Schneider, Rosalyn M.
Thurtell, Matthew J.
Eisele, Sylvia
Lincoff, Norah
Bala, Elisa
Leigh, R. John
author_sort Schneider, Rosalyn M.
collection PubMed
description When normal subjects fix their eyes upon a stationary target, their gaze is not perfectly still, due to small movements that prevent visual fading. Visual loss is known to cause greater instability of gaze, but reported comparisons with normal subjects using reliable measurement techniques are few. We measured binocular gaze using the magnetic search coil technique during attempted fixation (monocular or binocular viewing) of 4 individuals with childhood-onset of monocular visual loss, 2 individuals with late-onset monocular visual loss due to age-related macular degeneration, 2 individuals with bilateral visual loss, and 20 healthy control subjects. We also measured saccades to visual or somatosensory cues. We tested the hypothesis that gaze instability following visual impairment is caused by loss of inputs that normally optimize the performance of the neural network (integrator), which ensures both monocular and conjugate gaze stability. During binocular viewing, patients with early-onset monocular loss of vision showed greater instability of vertical gaze in the eye with visual loss and, to a lesser extent, in the normal eye, compared with control subjects. These vertical eye drifts were much more disjunctive than upward saccades. In individuals with late monocular visual loss, gaze stability was more similar to control subjects. Bilateral visual loss caused eye drifts that were larger than following monocular visual loss or in control subjects. Accurate saccades could be made to somatosensory cues by an individual with acquired blindness, but voluntary saccades were absent in an individual with congenital blindness. We conclude that the neural gaze-stabilizing network, which contains neurons with both binocular and monocular discharge preferences, is under adaptive visual control. Whereas monocular visual loss causes disjunctive gaze instability, binocular blindness causes both disjunctive and conjugate gaze instability (drifts and nystagmus). Inputs that bypass this neural network, such as projections to motoneurons for upward saccades, remain conjugate.
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spelling pubmed-35755042013-02-25 Neurological Basis for Eye Movements of the Blind Schneider, Rosalyn M. Thurtell, Matthew J. Eisele, Sylvia Lincoff, Norah Bala, Elisa Leigh, R. John PLoS One Research Article When normal subjects fix their eyes upon a stationary target, their gaze is not perfectly still, due to small movements that prevent visual fading. Visual loss is known to cause greater instability of gaze, but reported comparisons with normal subjects using reliable measurement techniques are few. We measured binocular gaze using the magnetic search coil technique during attempted fixation (monocular or binocular viewing) of 4 individuals with childhood-onset of monocular visual loss, 2 individuals with late-onset monocular visual loss due to age-related macular degeneration, 2 individuals with bilateral visual loss, and 20 healthy control subjects. We also measured saccades to visual or somatosensory cues. We tested the hypothesis that gaze instability following visual impairment is caused by loss of inputs that normally optimize the performance of the neural network (integrator), which ensures both monocular and conjugate gaze stability. During binocular viewing, patients with early-onset monocular loss of vision showed greater instability of vertical gaze in the eye with visual loss and, to a lesser extent, in the normal eye, compared with control subjects. These vertical eye drifts were much more disjunctive than upward saccades. In individuals with late monocular visual loss, gaze stability was more similar to control subjects. Bilateral visual loss caused eye drifts that were larger than following monocular visual loss or in control subjects. Accurate saccades could be made to somatosensory cues by an individual with acquired blindness, but voluntary saccades were absent in an individual with congenital blindness. We conclude that the neural gaze-stabilizing network, which contains neurons with both binocular and monocular discharge preferences, is under adaptive visual control. Whereas monocular visual loss causes disjunctive gaze instability, binocular blindness causes both disjunctive and conjugate gaze instability (drifts and nystagmus). Inputs that bypass this neural network, such as projections to motoneurons for upward saccades, remain conjugate. Public Library of Science 2013-02-18 /pmc/articles/PMC3575504/ /pubmed/23441203 http://dx.doi.org/10.1371/journal.pone.0056556 Text en https://creativecommons.org/publicdomain/zero/1.0/ This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
spellingShingle Research Article
Schneider, Rosalyn M.
Thurtell, Matthew J.
Eisele, Sylvia
Lincoff, Norah
Bala, Elisa
Leigh, R. John
Neurological Basis for Eye Movements of the Blind
title Neurological Basis for Eye Movements of the Blind
title_full Neurological Basis for Eye Movements of the Blind
title_fullStr Neurological Basis for Eye Movements of the Blind
title_full_unstemmed Neurological Basis for Eye Movements of the Blind
title_short Neurological Basis for Eye Movements of the Blind
title_sort neurological basis for eye movements of the blind
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3575504/
https://www.ncbi.nlm.nih.gov/pubmed/23441203
http://dx.doi.org/10.1371/journal.pone.0056556
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