Stable individual plasticity patterns in blindness: a longitudinal study

Rehabilitation for individuals with blindness remains a challenge, primarily due to the considerable variability in functional outcomes, despite supposedly successful restoration of the peripheral light sensitivity. Brain reorganization may be a limiting factor in allowing a person who has been blind for a substantial duration to regain sight. To identify potential candidates who may benefit most from rehabilitation, it is crucial to search for neuromarkers that can predict success. However, the visual cortex in blindness was suggested to partake in multiple networks over time, flexibly shifting its function based on task demands. This would make it impossible to reliably use its connectivity or responses as neuromarkers. Here we specifically tested whether this is the case, by examining the stability of individual connectivity patterns from the visual cortex in a group of eight congenitally blind individuals over a period of two years. Interestingly, our findings reveal that functional connectivity from the primary visual cortex in this small sample of repeatedly sampled congenitally blind individuals is both distinctive and remarkably stable over time. Using multivoxel pattern analysis, we show that the unique patterns of reorganization within the visual cortex allow to decode participant identity very accurately across the three scan intervals. These results align with recent evidence highlighting significant individual differences in visual cortex connectivity, indicating a consistent and distinct role for the visual cortex in blindness that may vary across individuals. In conclusion, our study sheds light on the stability of functional connectivity within the visual cortex of congenitally blind individuals, adding a potential to identify stable neuromarkers associated with sight rehabilitation success. Such neuromarkers could facilitate targeted and personalized treatment strategies, enhancing the overall efficacy of visual restoration efforts.