Can Short-Term Ocular Dominance Plasticity Provide a General Index to Visual Plasticity to Personalize Treatment in Amblyopia?

AbstractPurposeRecently, Lunghi et al showed that amblyopic eye’s visual acuity per se after 2 months of occlusion therapy could be predicted by a homeostatic plasticity, i.e., the temporary shift of ocular dominance observed after a 2-hour monocular deprivation, in children with anisometropic amblyopia(Lunghi et al., 2016). In this study, we assess whether the visual acuity improvement of the amblyopic eye measured after 2 months of occlusion therapy could be predicted by this plasticity.MethodsSeven children (6.86 ± 1.46 years old; SD) with anisometropic amblyopia participated in this study. All patients were newly diagnosed and had no treatment history before participating in our study. They had finished 2 months of refractive adaptation and then received a 4-hour daily fellow eye patching therapy with an opaque patch for a 2-month period. Best-corrected visual acuity of the amblyopic eye was measured before and after the patching therapy. The homeostatic plasticity was assessed by measuring the temporary shift of ocular dominance observed after 2 hours of occlusion for the amblyopic eye before the treatment started. A binocular phase combination paradigm was used for this test.ResultsWe found that there was no significant correlation between the temporary shift of ocular dominance observed after 2 hours of occlusion for the amblyopic eye before the treatment started and the visual acuity gain obtained by the amblyopic eye from 2-month of classical patching therapy. This result involving the short-term patching of the amblyopic eye is consistent with a reanalysis of Lunghi et al’ s data.ConclusionsOcular dominance plasticity does not provide an index of cortical plasticity in the general sense such that it could be used to predict acuity outcomes from longer term classical patching.

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Short-term plasticity in the visual thalamus

10.1101/2021.10.14.464354 ◽

2021 ◽

Author(s):

Jan W Kurzawski ◽

Claudia Lunghi ◽

Laura Biagi ◽

Michela Tosetti ◽

Maria Concetta Morrone ◽

...

Keyword(s):

Visual Cortex ◽

Visual Processing ◽

Ocular Dominance ◽

Monocular Deprivation ◽

Spatial Proximity ◽

Short Term ◽

Ocular Dominance Plasticity ◽

Short Term Plasticity ◽

Visual Thalamus ◽

Plasticity Effect

While there is evidence that the visual cortex retains a potential for plasticity in adulthood, less is known about the subcortical stages of visual processing. Here we asked whether short-term ocular dominance plasticity affects the visual thalamus. We addressed this question in normally sighted adult humans, using ultra-high field (7T) magnetic resonance imaging combined with the paradigm of short-term monocular deprivation. With this approach, we previously demonstrated transient shifts of perceptual eye dominance and ocular dominance in visual cortex (Binda et al., 2018). Here we report evidence for short-term plasticity in the ventral division of the pulvinar (vPulv), where the deprived eye representation was enhanced over the non-deprived eye. This pulvinar plasticity effect was similar as previously seen in visual cortex and it was correlated with the ocular dominance shift measured behaviorally. In contrast, there was no short-term plasticity effect in Lateral Geniculate Nucleus (LGN), where results were reliably different from vPulv, despite their spatial proximity. We conclude that the visual thalamus retains potential for short-term plasticity in adulthood; the plasticity effect differs across thalamic subregions, possibly reflecting differences in their cortical connectivity.

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Inverse occlusion, a binocularly motivated treatment for amblyopia

10.1101/418871 ◽

2018 ◽

Author(s):

Jiawei Zhou ◽

Yidong Wu ◽

Yiya Chen ◽

Xiaoxin Chen ◽

Yunjie Liang ◽

...

Keyword(s):

Laboratory Finding ◽

Ocular Dominance ◽

Contrast Ratio ◽

Primary Outcome Measure ◽

Secondary Outcome ◽

Short Term ◽

Ocular Dominance Plasticity ◽

Paired Samples ◽

Refractive Correction ◽

Stereo Acuity

AbstractRecent laboratory finding suggest that short-term patching the amblyopic eye (i.e., inverse occlusion) results in a larger and more sustained improvement in the binocular balance compared with normal controls. In this study, we investigate the cumulative effects of the short-term inverse occlusion in adults and old children with amblyopia. A prospective cohort study of 18 amblyopes (10-35 years old; 3 with strabismus) who have been subjected to 2 hours/day of inverse occlusion for 2 months. Patients who required refractive correction or whose refractive correction needed updating were given a 2-month period of refractive adaptation. The primary outcome measure was the binocular balance which was measured using a phase combination task, the secondary outcome measures were the best corrected visual acuity which was measured with a Tumbling E acuity chart and convert to logMAR units and the stereo acuity which was measured with the Random-dot preschool stereotest. The averaged binocular gain was 0.11 in terms of the effective contrast ratio (z = −2.344, p = 0.019, 2-tailed Related samples Wilcoxon Signed Ranks Test). The average acuity gain was 0.14 logMAR equivalent (t(17) = 0.13, p < 0.001, 2-tailed paired samples t-test). The averaged stereo acuity gain was 253 arc seconds (z = −2.689, p = 0.007). Based on more recent research concerning adult ocular dominance plasticity, contrary to current practice, patching the amblyopic eye makes more sense; comparable acuity benefits, better compliance, better binocular outcome and applicable to adults as well as old children.

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Optical TrkB activation in Parvalbumin interneurons regulates intrinsic states to orchestrate cortical plasticity

10.1101/2020.04.27.063503 ◽

2020 ◽

Author(s):

Frederike Winkel ◽

Mathias B. Voigt ◽

Giuliano Didio ◽

Salomé Matéo ◽

Elias Jetsonen ◽

...

Keyword(s):

Gene Expression ◽

Neuronal Plasticity ◽

Cortical Plasticity ◽

Ocular Dominance ◽

Neurotrophin Receptors ◽

Critical Periods ◽

Cortical Networks ◽

Ocular Dominance Plasticity ◽

Visual Plasticity ◽

Parvalbumin Interneurons

AbstractActivation state of Parvalbumin (PV) interneurons regulates neuronal plasticity, driving the closure of developmental critical periods and alternating between high and low plasticity states in response to experience in adulthood. We now show that PV plasticity states are regulated through the activation of TrkB neurotrophin receptors. Activation of an optically activatable TrkB (optoTrkB) specifically in PV interneurons switches adult cortical networks into a state of elevated plasticity within minutes by decreasing excitability of PV neurons. OptoTrkB activation induces changes in gene expression related to neuronal plasticity and excitability, and increases the phosphorylation of Kv3.1 channels. OptoTrkB activation shifted cortical networks towards a low PV configuration, promoting oscillatory synchrony and ocular dominance plasticity. Visual plasticity induced by fluoxetine was lost in mice lacking TrkB in PV neurons. Our data suggest a novel mechanism that dynamically regulates PV interneurons configuration state and orchestrates cortical networks during adulthood.Graphical Abstract

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Aerobic Exercise Effects on Ocular Dominance Plasticity with a Phase Combination Task in Human Adults

Neural Plasticity ◽

10.1155/2017/4780876 ◽

2017 ◽

Vol 2017 ◽

pp. 1-7 ◽

Cited By ~ 8

Author(s):

Jiawei Zhou ◽

Alexandre Reynaud ◽

Robert F. Hess

Keyword(s):

Aerobic Exercise ◽

Binocular Rivalry ◽

Ocular Dominance ◽

General Effect ◽

Short Term ◽

Ocular Dominance Plasticity ◽

Plasticity Effect ◽

Phase Combination ◽

Human Adults ◽

Normal Adults

Several studies have shown that short-term monocular patching can induce ocular dominance plasticity in normal adults, in which the patched eye becomes stronger in binocular viewing. There is a recent study showing that exercise enhances this plasticity effect when assessed with binocular rivalry. We address one question, is this enhancement from exercise a general effect such that it is seen for measures of binocular processing other than that revealed using binocular rivalry? Using a binocular phase combination task in which we directly measure each eye’s contribution to the binocularly fused percept, we show no additional effect of exercise after short-term monocular occlusion and argue that the enhancement of ocular dominance plasticity from exercise could not be demonstrated with our approach.

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Ocular Dominance Plasticity: Measurement Reliability and Variability

10.1101/2020.07.27.211144 ◽

2020 ◽

Author(s):

Seung Hyun Min ◽

Ling Gong ◽

Alex S. Baldwin ◽

Alexandre Reynaud ◽

Zhifen He ◽

...

Keyword(s):

Ocular Dominance ◽

Measurement Methods ◽

Monocular Deprivation ◽

Short Term ◽

Ocular Dominance Plasticity ◽

Physiological Basis ◽

Eye Dominance ◽

Phase Combination ◽

One And Many ◽

Test Retest Reliability

AbstractIn the last decade, studies have shown that short-term monocular deprivation strengthens the deprived eye’s contribution to binocular vision. However, the magnitude of the change in eye dominance after monocular deprivation (i.e., the patching effect) has been found to be different between for different methods and within the same method. There are three possible explanations for the discrepancy. First, the mechanisms underlying the patching effect that are probed by different measurement tasks might exist at different neural sites. Second, test-retest variability in the measurement might have led to inconsistencies, even within the same method. Third, the patching effect itself in the same subject might fluctuate across separate days or experimental sessions. To explore these possibilities, we assessed the test-retest reliability of the three most commonly used tasks (binocular rivalry, binocular combination, and dichoptic masking) and the repeatability of the shift in eye dominance after short-term monocular deprivation for each of the task. Two variations for binocular phase combination were used, at one and many contrasts of the stimuli. Also, two variations of the dichoptic masking task was tested, in which the orientation of the mask grating was either horizontal or vertical. This makes five different measurement methods in all. We hope to resolve some of the inconsistencies reported in the literature concerning this form of visual plasticity. In this study, we also aim to recommend a measurement method that will allow us to better understand its physiological basis and the underpinning of visual disorders.

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