Grant: CIHR-ICRH Travel Awards - General pool

Approximately 80% of stroke survivors experience upper limb motor deficits in subacute stages of recovery and only around half of them achieve full upper limb recovery six months after the cerebrovascular accident. Understanding the mechanisms underlying brain repair after stroke is a prerequisite to identifying rehabilitation targets to improve recovery. In this study we investigated the associations between Cortico-spinal excitability (CSE), a biomarker associated with upper-limb motor function poststroke, with the capacity to learn an upper-limb motor skill in 95 stroke survivors with cortical and subcortical lesions. Our research reveals, for the first time, that motor skill learning after stroke may depend on distinct corticospinal circuits based on lesion location, and suggest that alternative motor circuits may play a crucial role in preserving learning for lesions affecting deep subcortical networks. While better motor skill learning was associated with neurotypical excitatory patterns in cortical strokes, shifts from intracortical inhibition to facilitation accompanied learning in subcortical lesions. This study represents a step forward in unraveling the complex neurophysiology involved in recovery in humans after stroke and could provide valuable insights for the design and interpretation of future rehabilitation trials aimed at enhancing upper-limb motor recovery.