Exercise does not enhance short-term deprivation-induced ocular dominance plasticity: evidence from dichoptic surround suppression

Baldwin, Alex S.; Finn, Abigail E; Green, Hayden M; Hess, Robert F.

doi:10.1016/j.visres.2022.108123

Cited by 4 publications

(3 citation statements)

References 66 publications

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“…One such strategy is aerobic exercise (Sale et al., 2007). However, the effect of exercise on visual plasticity in normal adults remains inconclusive (Baldwin et al., 2022; Finn et al., 2019; Lunghi & Sale, 2015; Virathone et al., 2021; Zhou et al., 2017). Although not demonstrated, exercise is believed to modulate E/I balance (Bavelier et al., 2010; Sale & Berardi, 2015) by reducing GABAergic inhibition.…”

Section: Discussionmentioning

confidence: 99%

Metaplasticity: Dark exposure boosts local excitability and visual plasticity in adult human cortex

Min,

Wang,

Chen

et al. 2023

The Journal of Physiology

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An interlude of dark exposure for about 1 week is known to shift excitatory/inhibitory (E/I) balance of the mammalian visual cortex, promoting plasticity and accelerating visual recovery in animals that have experienced cortical lesions during development. However, the translational impact of our understanding of dark exposure from animal studies to humans remains elusive. Here, we used magnetic resonance spectroscopy as a probe for E/I balance in the primary visual cortex (V1) to determine the effect of 60 min of dark exposure, and measured binocular combination as a behavioural assay to assess visual plasticity in 14 normally sighted human adults. To induce neuroplastic changes in the observers, we introduced 60 min of monocular deprivation, which is known to temporarily shift sensory eye balance in favour of the previously deprived eye. We report that prior dark exposure for 60 min strengthens local excitability in V1 and boosts visual plasticity in normal adults. However, we show that it does not promote plasticity in amblyopic adults. Nevertheless, our findings are surprising, given the fact that the interlude is very brief. Interestingly, we find that the increased concentration of the excitatory neurotransmitter is not strongly correlated with the enhanced functional plasticity. Instead, the absolute degree of change in its concentration is related to the boost, suggesting that the dichotomy of cortical excitation and inhibition might not explain the physiological basis of plasticity in humans. We present the first evidence that an environmental manipulation that shifts cortical E/I balance can also act as a metaplastic facilitator for visual plasticity in humans. imageKey points A brief interlude (60 min) of dark exposure increased the local concentration of glutamine/glutamate but not that of GABA in the visual cortex of adult humans. After dark exposure, the degree of the shift in sensory eye dominance in favour of the previously deprived eye from short‐term monocular deprivation was larger than that from only monocular deprivation. The neurochemical and behavioural measures were associated: the magnitude of the shift in the concentration of glutamine/glutamate was correlated with the boost in perceptual plasticity after dark exposure. Surprisingly, the increase in the concentration of glutamine/glutamate was not correlated with the perceptual boost after dark exposure, suggesting that the physiological mechanism of how E/I balance regulates plasticity is not deterministic. In other words, an increased excitation did not unilaterally promote plasticity.

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Section: Discussionmentioning

confidence: 99%

Metaplasticity: Dark exposure boosts local excitability and visual plasticity in adult human cortex

Min,

Wang,

Chen

et al. 2023

The Journal of Physiology

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“…The quantitative measurement of suppression provides advantages in monitoring subtle changes in the disease and may facilitate a more accurate quantification of disease severity. Additionally, in the future, combining our test with some other treatments such as binocular vision training may be helpful in treating binocular disorders ( Chadnova et al, 2017 ; Sheynin et al, 2019 ; Baldwin et al, 2022 ). In short, our study suggests that our device could be a good choice to measure interocular suppression in young individuals with IXT.…”

Section: Discussionmentioning

confidence: 99%

Quantitative interocular suppression in children with intermittent exotropia

et al. 2023

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PurposeWe have demonstrated that the depth of unbalanced interocular suppression can be quantified by balancing the interocular luminance differences required when both eyes are viewing simultaneously. In this study, we aimed to investigate the applicability of this method in children with intermittent exotropia (IXT), offering a quantitative assessment of interocular suppression in individuals with binocular imbalance. Additionally, we evaluated its association with the clinical characteristics of IXT.MethodsInterocular suppression in IXT was quantitatively measured using a polarizer and neutral-density (ND) filters. The density of the ND filter was adjusted incrementally from 0.3ND to 3ND, with a step size of 0.3ND (a total of 10 levels). Our prospective study involved 46 patients with IXT (mean age: 10.12 ± 4.89 years; mean ± SD) and 24 normal observers (mean age: 7.88 ± 1.83 years).ResultsThe suppression test exhibited good test–retest reliability, supported by statistical analysis. We observed more pronounced interocular suppression in individuals with IXT compared to controls. Notably, the magnitude of suppression during distant and near viewing significantly differed in IXT (1.55 ± 0.93 vs. 0.57 ± 0.64; Z = 4.764, p < 0.001). Furthermore, we identified a positive correlation between interocular suppression and data obtained from the Worth-4-Dot test. Additionally, interocular suppression showed a significant association with distance control scores.ConclusionOur novel test offers a convenient and reliable means to quantify interocular suppression in patients with IXT. The quantitative assessment of interocular suppression provides a sensitive tool to evaluate the clinical characteristics of IXT.

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“…One failed in binocular fusion in the EEG pre-test, thus also quit from the rest of the experiment. The sample size was predetermined based on previous studies in this field ( Lunghi et al, 2015 ; Binda et al, 2018 ; Lyu et al, 2020 ; Virathone et al, 2021 ; Baldwin et al, 2022 ; Kurzawski et al, 2022 ). All participants were naive to the experimental hypotheses, had normal or corrected-to-normal vision.…”

Section: Methodsmentioning

confidence: 99%

Negligible contribution of adaptation of ocular opponency neurons to the effect of short-term monocular deprivation

Wang,

Song,

et al. 2024

Front. Psychol.

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IntroductionModeling work on binocular rivalry has described how ocular opponency neurons represent interocular conflict. These neurons have recently been considered to mediate an ocular dominance shift to the eye that has viewed a backward movie for long during which time the other eye is presented with a regular movie. Unlike typical short-term monocular deprivation, the visual inputs are comparable across eyes in that “dichoptic-backward-movie” paradigm. Therefore, it remains unclear whether the ocular opponency neurons are also responsible for the short-term monocular deprivation effect which is prevalently explained by the homeostatic compensation theory. We designed two experiments from distinct perspectives to investigate this question.MethodsIn Experiment 1, we mitigated the imbalance in the activity of opponency neurons between the two eyes during monocular deprivation by presenting video stimuli alternately. In Experiment 2, we directly evaluated the response of opponency neurons before and after monocular deprivation using SSVEP techniques.ResultsConsistent with each other, both experiments failed to provide reliable evidence supporting the involvement of ocular opponency neurons in the short-term monocular deprivation effect.DiscussionOur results suggest that ocular opponency neurons may not play an essential role in the short-term monocular deprivation effect, potentially due to interference from the homeostatic plasticity mechanism.

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Exercise does not enhance short-term deprivation-induced ocular dominance plasticity: evidence from dichoptic surround suppression

Cited by 4 publications

References 66 publications

Metaplasticity: Dark exposure boosts local excitability and visual plasticity in adult human cortex

Metaplasticity: Dark exposure boosts local excitability and visual plasticity in adult human cortex

Quantitative interocular suppression in children with intermittent exotropia

Negligible contribution of adaptation of ocular opponency neurons to the effect of short-term monocular deprivation

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