Abstract
Behavioral alterations emerging after central or peripheral vision loss suggest that cerebral reorganization occurs for both the afferented and deafferented early visual cortex (EVC). We explored the functional reorganization of the central and peripheral EVC following visual field defects specifically affecting central or peripheral vision. Compared to normally sighted, afferented central and peripheral EVC enhance their functional connectivity with areas involved in visual processing, whereas deafferented central and peripheral EVC increase their functional connectivity with more remote regions. The connectivity pattern of afferented EVC suggests adaptive changes that might enhance the visual processing capacity whereas the connectivity pattern of deafferented EVC may reflect the involvement of these regions in high-order mechanisms. Characterizing and understanding the plastic changes induced by these visual defects is essential for any attempt to develop efficient rehabilitation strategies.
Highlights
Adaptive strategies such as the eccentric fixation employed in the case of central visual field defects induce proportional functional changes in the peripheral early visual cortex (EVC)[5,6], providing some support for the first hypothesis that the residual afferent visual cortex reorganizes to compensate for the loss in sensory input
We selected participants suffering from a condition that induces progressive visual loss in either the central retina; i.e., Stargardt macular dystrophy, or the peripheral retina; i.e. retinitis pigmentosa and whose visual field defects met the selection criteria for our experiments
We explored the changes induced by partial visual loss by analyzing resting-state functional connectivity, a method that places few demands on patients since they perform no task during scan acquisition
Summary
Adaptive strategies such as the eccentric fixation employed in the case of central visual field defects induce proportional functional changes in the peripheral early visual cortex (EVC)[5,6], providing some support for the first hypothesis that the residual afferent visual cortex reorganizes to compensate for the loss in sensory input. Other authors[13,14,15] reported that adults with conditions inducing either central or peripheral field defects only exhibited task-related activation of the deafferented regions of the visual cortex This led to the third hypothesis of another type of reorganization in which the sensory-deprived visual regions contribute to higher-order mechanisms such as attention or mental imagery[13,14,15] or intervene in multisensory processing[16]. Factors such as the limited number of participants[10,11,12,13,14,15] and/or heterogeneity in the extent of visual field defects in the samples[10,11,12,13] may have contributed to these divergent results and preclude comparisons between the functional reorganization induced by central and peripheral visual loss. As a control, we investigated the possible FC changes in another topographic system, the somatosensory system
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