Electrical Stimulation of Spared Corticospinal Axons Augments Connections with Ipsilateral Spinal Motor Circuits after Injury

This study investigates how activity and injury contribute to the plasticity of the corticospinal (CS) system in mature animals. Researchers examined if activity-dependent plasticity could strengthen connections between spared CS axons and spinal motor circuits after injury. The researchers electrically stimulated CS tract axons in the medullary pyramid to study the effects of activity. To study injury, one pyramid was lesioned, modeling the sparse CS connections preserved after CNS injury. The study found that both stimulation and injury alone strengthened CS connectivity and increased outgrowth into the ipsilateral gray matter. The combination of stimulation and injury resulted in even stronger connections, particularly in the ventral motor territories of the spinal cord.

• 1
  Both electrical stimulation and injury alone strengthened ipsilateral corticospinal (CS) connectivity.
• 2
  Stimulation of spared axons after injury promoted outgrowth that reflected the sum of effects attributable to activity and injury alone.
• 3
  Combined injury and stimulation led to a novel pattern of terminations in the ventral horn.