Publication
Homonymous hemianopia (HH), a common visual impairment resulting from occipital lobe lesions, affects a significant number of stroke survivors. Intensive perceptual training can foster recovery, possibly by enhancing surviving visual pathways. This study employed cortico-cortical paired associative stimulation (ccPAS) to induce associative plasticity within the residual and bidirectional primary visual cortex (V1)-middle temporal area (MT) pathways in stroke patients. We used ccPAS, which is thought to tap into Hebbian-like spike-timing dependent plasticity, over a motion processing pathway in stroke patients to transiently improve visual motion discrimination in their blind field.Sixteen stroke patients participated in this double-blind, crossover study comparing the effects of bidirectional ccPAS (V1-to-MT or MT-to-V1) on motion discrimination and EEG-Granger Causality. Additionally, we explored potential multimodal sources of inter-individual variability.Results showed that MT-to-V1 ccPAS enhanced motion direction discrimination, but the expected electrophysiological increase in top-down MT-to-V1 inputs was observed only in patients who showed improvement in motion discrimination. Good responders to MT-V1 ccPAS also demonstrated improved functional coupling between the cortical motion pathway and other relevant areas in the visual network, as well as more preserved ipsilesional V1-MT structural integrity.These findings indicate that targeted ccPAS can effectively engage functionally relevant residual visual pathways in stroke-affected brains, potentially offering new avenues for patient stratification and visual recovery strategies. Bevilacqua et al. explore whether a novel brain stimulation method-cortico-cortical paired associative stimulation (ccPAS)-can improve vision in stroke patients with occipital lobe damage. They show that ccPAS can enhance motion direction discrimination and strengthen connections in visual pathways, highlighting its potential to aid visual recovery.