Vagus Nerve Stimulation Paired with Rehabilitative Training Enhances Motor Recovery after Bilateral Spinal Cord Injury to Cervical Forelimb Motor Pools

This study investigates whether vagus nerve stimulation (VNS) paired with rehabilitative training can improve motor recovery after spinal cord injury (SCI) that damages the motor neurons controlling distal forelimb muscles. Rats with bilateral SCI at C7/8 underwent rehabilitative training with or without paired VNS. The results showed that VNS paired with training significantly improved forelimb strength compared to training alone. The beneficial effects of VNS were not limited to the trained task, as they also generalized to similar, untrained forelimb tasks, such as the cylinder assessment and grip strength test. This suggests that VNS enhances synaptic plasticity in spared motor networks, increasing motor drive onto remaining alpha motor neurons. These findings indicate that damage to the motor neuron pools does not prevent VNS-dependent enhancement of recovery after SCI, supporting the potential of VNS therapy as a therapeutic intervention for incomplete cervical SCI in patients.

• 1
  VNS paired with rehabilitative training significantly increased recovery of volitional forelimb strength compared to equivalent rehabilitative training without VNS after bilateral spinal cord damage at C7/8.
• 2
  VNS-dependent enhancement of recovery generalized to two similar, but untrained, forelimb tasks, indicating that the benefits of VNS are not limited to the specific trained task.
• 3
  No differences were observed in lesion extent across groups, indicating that VNS does not promote neuroprotection to improve recovery.