Enhanced visual attentional modulation in patients with inherited peripheral retinal degeneration in the absence of cortical degeneration

PurposeStudies 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.MethodsWe 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 measuredResultsWe 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.ConclusionsWe 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.