Lilie Gailloud¹, Rebecca Millington-Truby¹, Hanna Willis^1,2, Lucy Starling¹, Matthew Cavanaugh³, Krystel Huxlin³, Marco Tamietto^4,5, Holly Bridge¹; ¹University of Oxford, ²École normale supérieure, ³University of Rochester, ⁴Tilburg University, ⁵University of Torino

Damage to the primary visual cortex (V1) following stroke typically causes contralesional visual field loss, yet many individuals retain residual vision (also known as blindsight), likely supported by extrastriate areas such as motion-sensitive hMT+. Here, we tested the hypothesis that extensive blind-field training restores vision in the blind field by modulating functional connectivity across V1, hMT+, and frontoparietal attentional regions. Seventeen participants with visual field deficits (5 female; 24-71 years; >6 months post-stroke) completed ≥6 months of blind-field motion discrimination training (2x20min/day; 102-271 sessions) and underwent pre- and post-training MRI. Sixteen controls (6 female; 28-71 years) were scanned once. Psychophysical measures included motion discrimination thresholds and detection of moving Gabors. Resting-state connectivity analyses identified regions showing BOLD correlations with ipsi- and contralesional V1, hMT+, intraparietal sulcus (IPS), and dorsolateral prefrontal cortex (DLPFC). Patient-control differences were assessed with two-sample t-tests; pre-post training effects with paired t-tests including performance as covariates (Z>2.3; cluster-corrected p<0.05). Relative to controls, stroke survivors showed widespread V1 hyperconnectivity, lower contralesional hMT+–V1 and IPS–V1 coupling, and greater ipsilesional hMT+–somatosensory and IPS–somatosensory connectivity, consistent with disrupted visual input and compensatory multisensory recruitment. Training-related motion discrimination improvements correlated with increased ipsi- and contralesional hMT+–paracingulate, ipsilesional DLPFC–V1 and hMT+, and contralesional DLPFC–V4 and hMT+ connectivity, suggesting top-down facilitation of residual motion processing. Gabor detection gains correlated with strengthened dorsal attention network connectivity, with increased ipsi- and contralesional IPS–IPL and precuneus coupling. Ipsi- and contralesional DLPFC–extrastriate (V2, V3, V4, and hMT+) connectivity also increased, underscoring the central role of frontoparietal regions. To conclude, visual improvements in cortically-blinded fields appear to depend critically on strengthening visuo-attentional connectivity to amplify residual signals. Rehabilitation should therefore not only re-engage spared visual circuits but actively boost attentional engagement, with multisensory and virtual reality-based approaches offering promising routes to more efficient recovery.