Retinotopy of the cortical lesion projection zone in macular degeneration F Cornelissen1, K Haak2, A B Morland3 |
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1University Medical Center Groningen, Netherlands |
| Macular degeneration (MD) causes lesions to the center of the retina. There is no cure for MD but several promising treatments aim at restoring retinal lesions. These treatments assume that the patient's brain can still process the retinal signals once they are restored, but whether this is correct has yet to be determined. In previous work, we established that long-term visual deprivation does not result in cortical remapping, while it does lead to cortical degeneration. Here, we used functional magnetic resonance imaging (fMRI) and a new data-analysis tool – connective field modeling – to evaluate retinotopy in the cortical lesion projection zone (LPZ). We found that connectivity between the LPZ in areas V1 and V2 is still retinotopically organized in MD, although less so than in controls with simulated retinal lesions. Moreover, the decreased connectivity in MD correlated strongly with fixation instability, but not with retinal lesion size. This suggests that the difference between MD patients and controls may be related to poor fixation and that the retinotopy of the LPZ remains largely intact, despite the prolonged loss of visual input. These results suggest that the restoration of sight in MD can probably assume largely unchanged cortical visual fields maps. |
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