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Enhanced visual attentional modulation in patients with inherited peripheral retinal degeneration in the absence of cortical degeneration
Author(s) -
Ferreira S.,
Andreia P.,
Quendera B.,
Silva E.,
Reis A.,
CasteloBranco M.
Publication year - 2017
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2017.0t056
Subject(s) - retinitis pigmentosa , visual field , visual cortex , neuroscience , retinal degeneration , retinal , stimulus (psychology) , degeneration (medical) , peripheral , psychology , ophthalmology , medicine , retina , cognitive psychology
Purpose Studies concerning the effects of peripheral retinal degeneration on visual cortical structure and function are scarce. Our work aimed to determine the effect of peripheral retinal dystrophy caused by Retinitis Pigmentosa on brain function and structure using magnetic resonance imaging, taking into account the effect of the preserved visual field extent and the disease onset age. Methods We included thirteen patients and twenty‐two matched controls. We analyzed cortical responses under attentional demands and passive viewing conditions while presenting a visual stimulus covering the central and paracentral visual field. Responses were studied in the visual cortical areas (V1, V2 and V3) and also in two cortical regions of interest corresponding to the preserved and the damaged visual field. The cortical thickness of visual areas was also measured Results We found that cortical visual responses under attentional demands were increased in patients with larger degeneration of visual field. Moreover, activation during the task condition was increased for patients in both cortical regions corresponding to the preserved and the damaged visual field, specifically in patients with severe visual field loss. These findings were observed in presence of preserved visual cortical structure. Conclusions We conclude that Retinitis Pigmentosa patients have enhanced visual attentional modulation despite their retinal degeneration, while cortical structure remains intact (with an relative increase in V2 thickness in patients with RP in early stages). The unmasking of feedback signals from higher level visual regions involved in attentional processes may explain the increased cortical responses. These findings are relevant in the context of the design of strategies for treating retinal diseases.