Contextual influences in the peripheral retina of patients with macular degeneration

Abstract 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 conne...

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Autores principales:	Giulio Contemori, Luca Battaglini, Clara Casco
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2019
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/6039016c3c1548d6aed8491243054797
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spelling	oai:doaj.org-article:6039016c3c1548d6aed84912430547972021-12-02T15:08:21ZContextual influences in the peripheral retina of patients with macular degeneration10.1038/s41598-019-45648-42045-2322https://doaj.org/article/6039016c3c1548d6aed84912430547972019-06-01T00:00:00Zhttps://doi.org/10.1038/s41598-019-45648-4https://doaj.org/toc/2045-2322Abstract 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.Giulio ContemoriLuca BattagliniClara CascoNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 9, Iss 1, Pp 1-10 (2019)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Giulio Contemori Luca Battaglini Clara Casco Contextual influences in the peripheral retina of patients with macular degeneration
description	Abstract 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.
format	article
author	Giulio Contemori Luca Battaglini Clara Casco
author_facet	Giulio Contemori Luca Battaglini Clara Casco
author_sort	Giulio Contemori
title	Contextual influences in the peripheral retina of patients with macular degeneration
title_short	Contextual influences in the peripheral retina of patients with macular degeneration
title_full	Contextual influences in the peripheral retina of patients with macular degeneration
title_fullStr	Contextual influences in the peripheral retina of patients with macular degeneration
title_full_unstemmed	Contextual influences in the peripheral retina of patients with macular degeneration
title_sort	contextual influences in the peripheral retina of patients with macular degeneration
publisher	Nature Portfolio
publishDate	2019
url	https://doaj.org/article/6039016c3c1548d6aed8491243054797
work_keys_str_mv	AT giuliocontemori contextualinfluencesintheperipheralretinaofpatientswithmaculardegeneration AT lucabattaglini contextualinfluencesintheperipheralretinaofpatientswithmaculardegeneration AT claracasco contextualinfluencesintheperipheralretinaofpatientswithmaculardegeneration
_version_	1718388187404959744

Contextual influences in the peripheral retina of patients with macular degeneration

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