Large-scale remapping of visual cortex is absent in adult humans with macular degeneration. Nature Neuroscience 14

nature neurOSCIenCe advance online publication a r t I C l e S The human brain contains maps of the retina on the surface of the occipital lobes 1 . Abnormal visual development can modify these retinotopic maps Several groups have investigated reorganization in human adult cortex when retinal lesions were acquired as a result of disease (macular degeneration). These studies have produced variable results, generating some controversy. One group 14 found no evidence of activity in parts of visual cortex that normally receive input from lesioned retina (the lesion projection zone) in a single, elderly individual. Another study Using methods that explicitly evaluate visual cortical maps, we sought to determine whether humans with lesions acquired in adulthood exhibit reorganization in the form of cortical remapping of visual input over the large-scale seen in individuals with congenital foveal loss of vision 6 . In contrast with prior studies largely restricted to a few individuals with juvenile forms of macular degeneration (JMD), we compared responses in a large number of individuals in two different age groups: those with JMD and those with the more common age-related form (AMD), and their age-matched controls. We found no evidence of large-scale remapping in early visual areas in adults with acquired retinal lesions. Indeed, the area of activity in primary visual cortex measured in these individuals was no different from that predicted on the basis of normal retinotopic maps. Furthermore, the absence of cortical remapping was not dependent on the age at which the individuals acquired retinal lesions in adulthood. RESULTS Cortical responses were measured in 16 individuals with macular degeneration (se

Large-scale remapping of visual cortex is absent in adult humans with macular degeneration

The occipital lobe contains retinotopic representations of the visual field. The representation of the central retina in early visual areas (V1-3) is found at the occipital pole. When the central retina is lesioned in both eyes by macular degeneration, this region of visual cortex at the occipital pole is accordingly deprived of input. However, even when such lesions occur in adulthood, some visually driven activity in and around the occipital pole can be observed. It has been suggested that this activity is a result of remapping of this area so that it now responds to inputs from intact, peripheral retina. We evaluated whether or not remapping of visual cortex underlies this activity. Our functional magnetic resonance imaging results provide no evidence of remapping, questioning the contemporary view that early visual areas of the adult human brain have the capacity to reorganize extensively