Longitudinal changes in the cortico-reticulospinal tract associated with high-intensity locomotor training in chronic stroke

Introduction: High-intensity locomotor training (HIT) is recommended for improving walking capacity, but treatment responses are variable. Understanding the brain changes underlying responsiveness to training could provide insight into this variability. Emerging evidence suggests upregulation of the contralesional cortico-reticulospinal tract (CRST) may contribute to walking function after stroke. However, it is unclear whether CRST upregulation is supportive or maladaptive, and no studies have examined CRST changes after HIT. This study investigated how CRST and corticospinal tract (CST) strength and laterality reorganize, and their relationship with walking capacity after locomotor HIT. Me