Topologic Reorganization of White Matter Connectivity Networks in Early-Blind Adolescents

Effect of Retinitis Pigmentosa Blindness on Functional Brain Network Measures

Our brain undergoes significant alteration in response to blindness. Understanding these neuroplastic changes and finding reliable methods for quantification of such reorganization is consequential for devising optimum sight restoration therapies and clinical rehabilitation. In recent years, graph theory measures have been applied to brain connectivity, but few studies have examined blindness-induced cortical alterations using these methods. In this study, we investigated alterations in key global and local measures of functional plasticity in the brain network after visual deprivation. Four resting-state functional MRI runs from 10 sighted and 10 blind subjects, with severe retinitis pigmentosa, provided data for our analysis. The whole-brain ROI-ROI resting-state functional connectivity (rsFC) matrices were created for all subjects. Using the resulting rsFC matrices, the global density and efficiency were extracted for the whole brain and the visual system. Additionally, weighted degree, as a local metric, was investigated for all the nodes in the functional brain network. Our results revealed a statistically significant decrease in global density and efficiency of the visual system and weighted degree for lower visual areas, following visual deprivation in the blind group. The explored network measures can serve as tools to gauge functional neuroplasticity following blindness, as a complement to the behavioral indices. Future investigation with a larger number of test subjects for this rare condition can enable correlation analysis with patients' characteristics and further verify the application of these metrics as biomarkers of brain reorganization following vision loss.