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Koen V. Haak, Antony B. Morland, Frans W. Cornelissen; Connective field estimates in the cortical lesion project zone of individuals with macular degeneration. Journal of Vision 2013;13(15):T11. doi: 10.1167/13.15.11.
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© ARVO (1962-2015); The Authors (2016-present)
Connective field modeling refers to a new functional MRI data-analysis that extends the model-based procedure of estimating a voxel's population receptive field (pRF) towards an estimation of a voxel's connective field—just as the pRF predicts the activity of a voxel as a function of visual field position, the connective field of a voxel predicts the activity as a function on the cortical surface. Unlike the stimulus-referred pRF, the neural-referred connective field also captures the brain activity that occurs in the absence of visual stimulation. This feature is important, because it allows for evaluating the topographic organization of visual brain areas that cannot be visually stimulated. Here, we apply connective field modeling to examine the topography of the cortical lesion projection zone (LPZ) in individuals with bilateral retinal lesions due to macular degeneration (MD). By definition, the LPZ cannot be visually stimulated, so the topography of the LPZ can only be inferred from spontaneous brain activity. We find that the connective fields inside the LPZ are still topographically organized, but less so than in controls with simulated retinal lesions. However, we also find that the decreased connective field topography in MD is largely dependent on fixation instability. These results suggest, therefore, that the topographic configuration of the LPZ remains largely intact despite the prolonged loss of visual input following MD. This result is reassuring, because it means that future treatments aimed at restoring the retina would probably not require accounting for the potential of brain changes following prolonged visual deprivation.
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