What Is Being Trained? How Divergent Forms of Plasticity Compete To Shape Locomotor Recovery after Spinal Cord Injury

Spinal cord injury (SCI) often leads to motor and sensory system dysfunction, resulting in paralysis, sensory changes, and pain. Effective rehabilitation strategies are challenging due to the multifaceted nature of SCI. Researchers are exploring the potential of spinal cord plasticity to improve locomotor recovery. Intensive training post-SCI can improve lower extremity function by engaging the spinal cord's locomotor circuitry. Appropriate sensory input is crucial for adaptive plasticity, while inappropriate input can lead to maladaptive effects like pain and spasticity. This review examines parameters that foster adaptive plasticity and those that produce maladaptive plasticity, which hinders neurorehabilitation. It also discusses the timing of afferent input after SCI to promote locomotor recovery and suggests a synaptic mechanism for maladaptive plasticity.

• 1
  Adaptive spinal training requires adequate and appropriate afferent input to modulate spinal circuitry, like the central pattern generator (CPG), for rhythmic locomotor activities with proprioceptive and sensory feedback.
• 2
  Maladaptive plasticity, such as hyper-reflexia and chronic central pain, can spontaneously emerge after SCI and undermine common adaptive rehabilitation methods.
• 3
  Targeting synaptic mechanisms of intraspinal changes, like CP-AMPAR activity, has the potential to reverse maladaptive plasticity and improve locomotor recovery.