Abstract: Traumatic spinal cord injury (SCI) leads to chronic locomotor impairment and disability. Unfortunately, there are no effective treatments currently available for SCI patients (Bradbury and Burnside, 2019). Developing novel repair interventions to mitigate the devastating nature of SCI and translating them clinically are urgent medical needs to improve the quality of life of patients with SCI. The lumbar spinal motoneurons (MNs) are the final common pathway for hindlimb locomotion since all neural activities that influence hindlimb movement converging upon these neurons. With above-level (cervical and thoracic) SCIs, the lumbar MNs are not directly injured by the initial mechanical impact, but they undergo profound degeneration with dendritic atrophy and synaptic stripping due to a trauma-induced decrease of supraspinal and propriospinal innervations, leading to impaired locomotor function (Figure 1A; Wang et al., 2018). While most SCI studies have been focused on the neuroregeneration or neuroprotection of injured spinal cord at the lesion site, few studies have explored the potential benefit of modulating lumbar motor circuitry for locomotor recovery after an above-level SCI. Filling this gap is an important task for developing the care and treatment of SCI.