Spinal cord injury disrupts the descending command from the brain and causes a range of motor deficits. Here, we use optogenetic tools to investigate the functional plasticity of the glutamatergic reticulospinal drive of the medullary reticular formation after a lateral thoracic hemisection in female mice. Sites evoking stronger excitatory descending drive in intact conditions are the most impaired after injury, whereas those associated with a weaker drive are potentiated. After lesion, pro- and anti-locomotor activities (that is, initiation/acceleration versus stop/deceleration) are overall preserved. Activating the descending reticulospinal drive improves stepping ability on a flat surface of chronically impaired injured mice, and its priming enhances recovery of skilled locomotion on a horizontal ladder. This study highlights the resilience and capacity for reorganization of the glutamatergic reticulospinal command after injury, along with its suitability as a therapeutical target to promote functional recovery.

脊髓损伤会扰乱大脑的下行命令，并导致一系列运动缺陷。在这里，我们使用光遗传学工具来研究雌性小鼠侧胸半切后谷氨酸能网状脊髓驱动髓质网状结构的功能可塑性。在完整的条件下唤起更强的兴奋性下行驱动力的部位在受伤后受损最严重，而那些与驱动力较弱相关的部位则被增强。损伤后，促运动和抗运动活动（即启动/加速与停止/减速）总体保留。激活下降的网状脊髓驱动可提高长期受损小鼠在平坦表面上的行走能力，并且其启动可增强水平梯子上熟练运动的恢复。这项研究强调了损伤后谷氨酸能网状脊髓指挥重组的弹性和能力，及其作为促进功能恢复的治疗靶点的适用性。