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Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry

Neuromodulation of the primary visual cortex using anodal transcranial direct current stimulation (a-tDCS) can alter visual perception and enhance neuroplasticity. However, the mechanisms that underpin these effects are currently unknown. When applied to the motor cortex, a-tDCS reduces the concentr...

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Autores principales: Abuleil, Dania, McCulloch, Daphne, Thompson, Benjamin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861428/
https://www.ncbi.nlm.nih.gov/pubmed/33539443
http://dx.doi.org/10.1371/journal.pone.0239349
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author Abuleil, Dania
McCulloch, Daphne
Thompson, Benjamin
author_facet Abuleil, Dania
McCulloch, Daphne
Thompson, Benjamin
author_sort Abuleil, Dania
collection PubMed
description Neuromodulation of the primary visual cortex using anodal transcranial direct current stimulation (a-tDCS) can alter visual perception and enhance neuroplasticity. However, the mechanisms that underpin these effects are currently unknown. When applied to the motor cortex, a-tDCS reduces the concentration of the inhibitory neurotransmitter gamma aminobutyric acid (GABA), an effect that has been linked to increased neuroplasticity. The aim of this study was to assess whether a-tDCS also reduces GABA-mediated inhibition when applied to the human visual cortex. Changes in visual cortex inhibition were measured using the mixed percept duration in binocular rivalry. Binocular rivalry mixed percept duration has recently been advocated as a direct and sensitive measure of visual cortex inhibition whereby GABA agonists decrease mixed percept durations and agonists of the excitatory neurotransmitter acetylcholine (ACH) increase them. Our hypothesis was that visual cortex a-tDCS would increase mixed percept duration by reducing GABA-mediated inhibition and increasing cortical excitation. In addition, we measured the effect of continuous theta-burst transcranial magnetic stimulation (cTBS) of the visual cortex on binocular rivalry dynamics. When applied to the motor or visual cortex, cTBS increases GABA concentration and we therefore hypothesized that visual cortex cTBS would decrease the mixed percept duration. Binocular rivalry dynamics were recorded before and after active and sham a-tDCS (N = 15) or cTBS (N = 15). Contrary to our hypotheses, a-tDCS had no effect, whereas cTBS increased mixed percepts during rivalry. These results suggest that the neurochemical mechanisms of a-tDCS may differ between the motor and visual cortices.
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spelling pubmed-78614282021-02-12 Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry Abuleil, Dania McCulloch, Daphne Thompson, Benjamin PLoS One Research Article Neuromodulation of the primary visual cortex using anodal transcranial direct current stimulation (a-tDCS) can alter visual perception and enhance neuroplasticity. However, the mechanisms that underpin these effects are currently unknown. When applied to the motor cortex, a-tDCS reduces the concentration of the inhibitory neurotransmitter gamma aminobutyric acid (GABA), an effect that has been linked to increased neuroplasticity. The aim of this study was to assess whether a-tDCS also reduces GABA-mediated inhibition when applied to the human visual cortex. Changes in visual cortex inhibition were measured using the mixed percept duration in binocular rivalry. Binocular rivalry mixed percept duration has recently been advocated as a direct and sensitive measure of visual cortex inhibition whereby GABA agonists decrease mixed percept durations and agonists of the excitatory neurotransmitter acetylcholine (ACH) increase them. Our hypothesis was that visual cortex a-tDCS would increase mixed percept duration by reducing GABA-mediated inhibition and increasing cortical excitation. In addition, we measured the effect of continuous theta-burst transcranial magnetic stimulation (cTBS) of the visual cortex on binocular rivalry dynamics. When applied to the motor or visual cortex, cTBS increases GABA concentration and we therefore hypothesized that visual cortex cTBS would decrease the mixed percept duration. Binocular rivalry dynamics were recorded before and after active and sham a-tDCS (N = 15) or cTBS (N = 15). Contrary to our hypotheses, a-tDCS had no effect, whereas cTBS increased mixed percepts during rivalry. These results suggest that the neurochemical mechanisms of a-tDCS may differ between the motor and visual cortices. Public Library of Science 2021-02-04 /pmc/articles/PMC7861428/ /pubmed/33539443 http://dx.doi.org/10.1371/journal.pone.0239349 Text en © 2021 Abuleil et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Abuleil, Dania
McCulloch, Daphne
Thompson, Benjamin
Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry
title Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry
title_full Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry
title_fullStr Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry
title_full_unstemmed Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry
title_short Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry
title_sort visual cortex ctbs increases mixed percept duration while a-tdcs has no effect on binocular rivalry
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861428/
https://www.ncbi.nlm.nih.gov/pubmed/33539443
http://dx.doi.org/10.1371/journal.pone.0239349
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