Functional connectivity interacts with visual perceptual learning for visual field recovery in chronic stroke

A reciprocal relationship between perceptual learning and functional brain changes towards perceptual learning effectiveness has been demonstrated previously; however, the underlying neural correlates remain unclear. Further, visual perceptual learning (VPL) is implicated in visual field defect (VFD) recovery following chronic stroke. We investigated resting-state functional connectivity (RSFC) in the visual cortices associated with mean total deviation (MTD) scores for VPL-induced VFD recovery in chronic stroke. Patients with VFD due to chronic ischemic stroke in the visual cortex received 24 VPL training sessions over 2 months, which is a dual discrimination task of orientation and letters. At baseline and two months later, the RSFC in the ipsilesional, interhemispheric, and contralesional visual cortices and MTD scores in the affected hemi-field were assessed. Interhemispheric visual RSFC at baseline showed the strongest correlation with MTD scores post-2-month VPL training. Notably, only the subgroup with high baseline interhemispheric visual RSFC showed significant VFD improvement following the VPL training. The interactions between the interhemispheric visual RSFC at baseline and VPL led to improvement in MTD scores and largely influenced the degree of VFD recovery. The interhemispheric visual RSFC at baseline could be a promising brain biomarker for the effectiveness of VPL-induced VFD recovery.