Abstract
Macular degeneration (MD) accounts for about half of all vision impairment or blind registrations in the developed world. It results in reduced central vision and impairment in tasks of daily living such as reading, driving and recognizing faces. In the human brain, the occipital lobe contains retinotopic representations of the visual field and the representation of the central retina in early visual areas is found at the occipital pole. Following loss of central vision, some studies have suggested that the portion of the primary visual cortex that would normally respond to central vision responds to attended peripheral visual stimuli. Some studies have suggested that this results from changes in top-down signals from regions that are higher in the cortical hierarchy. It is not known how connectivity between V1 and higher order areas changes following macular degeneration. Using BOLD fMRI, we measured changes in functional connectivity to primary visual cortex in a group of patients with central vision loss. We find that local functional connectivity between portions of V1 representing central vision and occipital regions representing peripheral vision are reduced in patients with MD relative to controls. Further, patients with MD showed relatively increased connectivity between V1 and the caudate. These results imply that one result of macular degeneration is a shift of connection patterns of V1.
Meeting abstract presented at VSS 2014