Spontaneous and training-induced cortical plasticity in MD patients: Hints from lateral masking

Maniglia, Marcello; Soler, V.; Cottereau, Benoit R.; Trotter, Yves

doi:10.1038/s41598-017-18261-6

Cited by 23 publications

(33 citation statements)

References 47 publications

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“…It should be noted that our training protocol is different from typical perceptual learning studies. Previous psychophysical studies have shown that training enhances the ability to identify or detect the target in the midst of flankers (Sun et al, 2010;Hussain et al, 2012;Mayhew et al, 2012;Zhu et al, 2016;Maniglia et al, 2018). In these studies, the same task was used in both the training and test phases, and the learning effect was often specific to features of the trained stimulus.…”

Section: Orymentioning

confidence: 99%

Cortical reorganization of peripheral vision induced by simulated central vision loss

Chen

Shin²,

Millin

et al. 2019

J. Neurosci.

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When one's central vision is deprived, a spared part of the peripheral retina acts as a pseudofovea for fixation. The neural mechanisms underlying this compensatory adjustment remain unclear. Here we report cortical reorganization induced by simulated central vision loss. Human subjects of both sexes learned to place the target at an eccentric retinal locus outside their blocked visual field for objecttracking. Before and after training, we measured visual crowding-a bottleneck of object identification in peripheral vision, using psychophysics and fMRI. We found that training led to an axis-specific reduction of crowding. The change of the crowding effect was reflected in the change of BOLD signal, as a release of cortical suppression in multiple visual areas starting as early as V1. Our findings suggest that the adult visual system is capable of reshaping its oculomotor control and sensory coding to adapt to impoverished visual input.

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Section: Orymentioning

confidence: 99%

Cortical reorganization of peripheral vision induced by simulated central vision loss

Chen

Shin²,

Millin

et al. 2019

J. Neurosci.

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“…Previous studies have observed that collinear lateral inhibition can be reduced using perceptual learning in observers with normal vision 12 and observers with macular degeneration 10 . Maniglia et al 12 reported an approximately 40% reduction of peripheral collinear lateral inhibition after training in healthy observers.…”

Section: Discussionmentioning

confidence: 96%

Anodal transcranial direct current stimulation reduces collinear lateral inhibition in normal peripheral vision

Raveendran

Tsang

Tiwana

et al. 2019

Preprint

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AbstractCollinear flanking stimuli can reduce the detectability of a Gabor target presented in peripheral vision. This phenomenon is called collinear lateral inhibition and it may contribute to crowding in peripheral vision. Perceptual learning can reduce collinear lateral inhibition in peripheral vision, however intensive training is required. Our aim was to assess whether modulation of collinear lateral inhibition can be achieved within a short time-frame using a single 20-minute session of primary visual cortex anodal transcranial direct current stimulation (a-tDCS). Thirteen observers with normal vision performed a 2AFC contrast detection task with collinear flankers positioned at a distance of 2λ from the target (lateral inhibition) or 6λ (control condition). The stimuli were presented 6° to the left of a central cross and fixation was monitored with an infra-red eye tracker. Participants each completed two randomly sequenced, single-masked stimulation sessions; real anodal tDCS and sham tDCS. For the 2λ separation condition, a-tDCS induced a significant reduction in detection threshold (reduced lateral inhibition). Sham stimulation had no effect. No effects of a-tDCS were observed for the 6λ separation condition. This result lays the foundation for future work investigating whether a-tDCS may be useful as a visual rehabilitation tool for individuals with central vision loss who are reliant on peripheral vision.

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“…In this case, with the low contrast target, we would have obtained increased contrast enhancement at the range of target-to-flanker distances at which facilitation occurs in normal vision. In the previous literature, the reduced collinear inhibition found in MD has been interpreted as a sign of neural plasticity, linked with a change in receptive field size 35,49 . We shed new light on this phenomenon and propose a different interpretation.…”

Section: Discussionmentioning

confidence: 96%

“…Since lateral connectivity has been shown to increase with practice in normal 31,34,45 and pathological vision 46–48 , use-dependent cortical reorganization might change the observed contextual influences. A partial support for the cortical reorganization hypothesis comes from recent papers showing that MD patients exhibited a modulation of contextual influences in respect of controls 35,49 . In the present study, we further address this issue attempting to specify the underlying mechanism.…”

Section: Introductionmentioning

confidence: 99%

Contextual influences in the peripheral retina of patients with macular degeneration

Contemori

Battaglini

2019

Sci Rep

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Macular degeneration (MD) is the leading cause of low vision in the elderly population worldwide. In case of complete bilateral loss of central vision, MD patients start to show a preferred retinal region for fixation (PRL). Previous literature has reported functional changes that are connected with the emergence of the PRL. In this paper, we question whether the PRL undergoes a use-dependent cortical reorganization that alters the range of spatial lateral interactions between low-level filters. We asked whether there is a modulation of the excitatory/inhibitory lateral interactions or whether contextual influences are well accounted for by the same law that describes the integration response in normal viewers. In a group of 13 MD patients and 7 age-matched controls, we probed contextual influences by measuring the contrast threshold for a vertical target Gabor, flanked by two collinear high-contrast Gabors. Contextual influences of the collinear flankers were indicated by the changes in contrast threshold obtained at different target-to-flanker distances (λs) relative to the baseline orthogonal condition. Results showed that MDs had higher thresholds in the baseline condition and functional impairment in the identification tasks. Moreover, at the shortest λ, we found facilitatory rather than inhibitory contextual influence. No difference was found between the PRL and a symmetrical retinal position (non-PRL). By pulling together data from MD and controls we showed that in the periphery this inversion occurs when the target threshold approach the flankers’ contrast (about 1:3 ratio) and that for patients it does occur in both the PRL and a symmetrical retinal position (non-PRL). We conclude that contrary to previous interpretations, this modulation doesn’t seem to reflect use-dependent cortical reorganization but rather, it might result from a reduction of contrast gain for the target that promotes target-flankers grouping.

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Spontaneous and training-induced cortical plasticity in MD patients: Hints from lateral masking

Cited by 23 publications

References 47 publications

Cortical reorganization of peripheral vision induced by simulated central vision loss

Cortical reorganization of peripheral vision induced by simulated central vision loss

Anodal transcranial direct current stimulation reduces collinear lateral inhibition in normal peripheral vision

Contextual influences in the peripheral retina of patients with macular degeneration

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