Anodal Transcranial Direct Current Stimulation Transiently Improves Contrast Sensitivity and Normalizes Visual Cortex Activation in Individuals With Amblyopia

Spiegel, D.; Byblow, Winston D.; Hess, Robert F.; Thompson, Benjamin

doi:10.1177/1545968313491006

Cited by 93 publications

(82 citation statements)

References 53 publications

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“…The stimulation parameters (current intensity and duration) were chosen in accordance with the safety criteria, for preventing any side-effects caused by cortical excitability modulation (Nitsche et al, , 2008Poreisz, Boros, Antal, & Paulus, 2007), and were commonly used in previous experiments for exploring visual cortex functions (e.g., Antal et al, 2004;Spiegel, Byblow, Hess, & Thompson, 2013;Spiegel, Hansen, Byblow, & Thompson, 2012;Vigan o et al, 2013). The stimulation intensity and duration were at the upper ends of tDCS protocols in order to ensure, as much as possible, that effects of tDCS would not be offset by the effects of presenting the potent gratings themselves.…”

Section: Tdcs Stimulationmentioning

confidence: 99%

Stimulating the aberrant brain: Evidence for increased cortical hyperexcitability from a transcranial direct current stimulation (tDCS) study of individuals predisposed to anomalous perceptions

Braithwaite

Mevorach

Takahashi

2015

Cortex

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Findings from neurological and clinical groups have shown that increased predisposition to anomalous experience/aura reflects an elevation in aberrant neural processes in the brain. However, studies of anomalous experiences in non-clinical/non-neurological groups are less clear on this matter and are more typically confined to subjective questionnaire measures alone. The current investigation, the first to our knowledge, carried out a transcranial Direct Current Stimulation (tDCS) study of cortical hyperexcitability, and its association with anomalous experience in non-clinical/non-neurological groups. Sixty participants completed; (i) both excitatory (anodal) and inhibitory (cathodal) brain stimulation conditions of the visual cortex; (ii) a computerised pattern-glare task, where observers reported phantom visual distortions from viewing highly irritable visual patterns (a metric of cortical hyperexcitability), and; (iii) questionnaire measures of predisposition to anomalous perceptions. There were no reliable signs of cortical hyperexcitability (via pattern-glare tasks) when collapsed across the whole sample. However, a significant positive correlation between predisposition to anomalous experience and elevated signs of cortical hyperexcitability was observed. Crucially, there was a significant negative correlation between tDCS stimulatory conditions. A visual cortex that reacted more strongly to excitatory stimulation, responded less well to inhibitory suppression, and this pattern was related to predisposition to anomalous perceptions. Both findings are consistent with the presence of a hyperexcitable cortex. Collectively the present findings provide objective evidence that the brains of individuals predisposed to anomalous experiences/hallucinations can be hyperexcitable - even in the non-clinical/non-neurological population. These data are consistent with continuum models of anomalous experience and have important implications for contemporary theories of aberrations in self-consciousness.

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Section: Tdcs Stimulationmentioning

confidence: 99%

Stimulating the aberrant brain: Evidence for increased cortical hyperexcitability from a transcranial direct current stimulation (tDCS) study of individuals predisposed to anomalous perceptions

Braithwaite

Mevorach

Takahashi

2015

Cortex

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“…This has led to the development of amblyopia treatment interventions designed to reduce suppressive mechanisms within the human visual cortex [11,[20][21][22][23][24][25][26]. One approach, based on psychophysical models of binocular vision and supported by initial clinical studies in adults [11,23,27] and children [22] involves dichoptic (separate images to each eye) presentation of high contrast images to the amblyopic eye and lower contrast images to the fellow eye.…”

Section: Introductionmentioning

confidence: 99%

“…The use of noninvasive brain stimulation techniques for the treatment of amblyopia is developing rapidly [25,26,32], and tDCS is particularly attractive owing to its low cost and the possibility that it can be used in the patient's own home [33]. Anodal tDCS (a-tDCS) tends to increase and cathodal tDCS (c-tDCS) tends to decrease excitability in the stimulated region.…”

Section: Introductionmentioning

confidence: 99%

Transcranial Direct Current Stimulation Enhances Recovery of Stereopsis in Adults With Amblyopia

et al. 2013

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Amblyopia is a neurodevelopmental disorder of vision caused by abnormal visual experience during early childhood that is often considered to be untreatable in adulthood. Recently, it has been shown that a novel dichoptic videogamebased treatment for amblyopia can improve visual function in adult patients, at least in part, by reducing inhibition of inputs from the amblyopic eye to the visual cortex. Non-invasive anodal transcranial direct current stimulation has been shown to reduce the activity of inhibitory cortical interneurons when applied to the primary motor or visual cortex. In this doubleblind, sham-controlled cross-over study we tested the hypothesis that anodal transcranial direct current stimulation of the visual cortex would enhance the therapeutic effects of dichoptic videogame-based treatment. A homogeneous group of 16 young adults (mean age 22.1±1.1 years) with amblyopia were studied to compare the effect of dichoptic treatment alone and dichoptic treatment combined with visual cortex direct current stimulation on measures of binocular (stereopsis) and monocular (visual acuity) visual function. The combined treatment led to greater improvements in stereoacuity than dichoptic treatment alone, indicating that direct current stimulation of the visual cortex boosts the efficacy of dichoptic videogamebased treatment. This intervention warrants further evaluation as a novel therapeutic approach for adults with amblyopia.

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“…Some improvement in contrast sensitivity with the sole use of brain stimulation, so far, has been observed in individuals with amblyopia after the administration of either anodal tDCS (Spiegel, Byblow, Hess, & Thompson, 2013) or high-frequency repetitive TMS (Clavagnier, Thompson, & Hess, 2013;Thompson, Mansouri, Koski, & Hess, 2008). Although here, improvement on CS is much more limited (to a single spatial frequency) than when combined with PL, suggesting a weaker effect of tRNS in the absence of a behavioural task.…”

Section: Discussionmentioning

confidence: 59%

The application of online transcranial random noise stimulation and perceptual learning in the improvement of visual functions in mild myopia

2016

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It has recently been demonstrated how perceptual learning, that is an improvement in a sensory/perceptual task upon practice, can be boosted by concurrent high-frequency transcranial random noise stimulation (tRNS). It has also been shown that perceptual learning can generalize and produce an improvement of visual functions in participants with mild refractive defects.By using three different groups of participants (single-blind study), we tested the efficacy of a short training (8 sessions) using a single Gabor contrast-detection task with concurrent hftRNS in comparison with the same training with sham stimulation or hf-tRNS with no concurrent training, in improving visual acuity (VA) and contrast sensitivity (CS) of individuals with uncorrected mild myopia.A short training with a contrast detection task is able to improve VA and CS only if coupled with hf-tRNS, whereas no effect on VA and marginal effects on CS are seen with the sole administration of hf-tRNS.Our results support the idea that, by boosting the rate of perceptual learning via the modulation of neuronal plasticity, hf-tRNS can be successfully used to reduce the duration of the perceptual training and/or to increase its efficacy in producing perceptual learning and generalization to improved VA and CS in individuals with uncorrected mild myopia.

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Anodal Transcranial Direct Current Stimulation Transiently Improves Contrast Sensitivity and Normalizes Visual Cortex Activation in Individuals With Amblyopia

Abstract: These preliminary results suggest that a-tDCS deserves further investigation as a potential tool to enhance amblyopia treatment outcomes in adults.

Cited by 93 publications

References 53 publications

Stimulating the aberrant brain: Evidence for increased cortical hyperexcitability from a transcranial direct current stimulation (tDCS) study of individuals predisposed to anomalous perceptions

Stimulating the aberrant brain: Evidence for increased cortical hyperexcitability from a transcranial direct current stimulation (tDCS) study of individuals predisposed to anomalous perceptions

Transcranial Direct Current Stimulation Enhances Recovery of Stereopsis in Adults With Amblyopia

The application of online transcranial random noise stimulation and perceptual learning in the improvement of visual functions in mild myopia

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