Developmental Changes in Locomotion and Sensorimotor Reflexes Following Spinal Cord Transection

The developmental trajectory of weight-bearing locomotion and sensorimotor reflexes following a spinal cord injury, as well as the mechanisms for plasticity, remain unclear. In rats, the second postnatal week is a critical period for the development and recovery of spinal sensorimotor function. The purpose of the present study was to characterize developmental changes during this time frame to provide a basis for potential interventions and future research. Rats underwent a complete low-thoracic (T8-T10) spinal cord transection surgery, or sham procedure, on postnatal day (P)1. Spontaneous locomotion and sensorimotor reflexes (surface righting, hindlimb placing, and crossed-extensor reflex) were tested on P7, P14, or P21. Results show that spinal-transected and sham rats exhibited the same amount of spontaneous locomotion, but the degree of relative weight bearing on the hindlimbs was different between groups and changed over time. Reflex findings showed that throughout the neonatal period, the isolated lumbar spinal cord can respond to sensory input and execute coordinated motor output following spinal cord transection. These insights contribute to understanding the developmental trajectory of spinal cord function after injury and provide a foundation for interventions to enhance recovery outcomes.