The Gigantocellular Reticular Nucleus Plays a Significant Role in Locomotor Recovery after Incomplete Spinal Cord Injury

Following a spinal cord injury, the brainstem, traditionally seen as poorly adaptable, exhibits spontaneous anatomic plasticity, especially in projections from the gigantocellular reticular nucleus (NRG). This study investigates the functional importance of reticulospinal fiber growth after spinal cord injury. The research examines how local rewiring of damaged projections and compensatory outgrowth of spared axons contribute to motor recovery. Using chemogenetic silencing in rats, the study assessed the role of NRG fibers in various aspects of recovered limb functions during walking and swimming. The findings demonstrate that both locally rewired and compensatory NRG plasticity are essential for improved stepping performance after spinal cord injury. This suggests that these adaptations are causative in the observed functional recovery seen in both animals and human patients.

• 1
  Locally rewired and compensatory NRG fibers are responsible for different aspects of recovered forelimb and hindlimb functions, including stability, strength, coordination, speed, and timing.
• 2
  Both locally rewired and compensatory NRG plasticity are crucial for recovered function during walking and swimming, while the contribution of locally rewired NRG plasticity to wading performance is limited.
• 3
  The study demonstrates comprehensively that locally rewired as well as compensatory plasticity of reticulospinal axons functionally contribute to the observed spontaneous improvement of stepping performance after incomplete SCI.