Spinal reflex conditioning: Mechanisms and implications

Abstract

Operant conditioning protocols that induce and maintain specific descending influence over spinal cord reflex pathways can gradually change these reflexes. These protocols create a complex hierarchy of plasticity in which plasticity in the brain induces and maintains the plasticity in the spinal cord that directly underlies reflex change. Thus, they provide a powerful model for studying the substrates of motor learning. In addition, because spinal cord reflexes contribute to behaviors such as locomotion, and because abnormalities in these reflexes often contribute to the motor impairments caused by spinal cord injury and other disorders, operant conditioning protocols provide a promising new therapeutic approach to improving recovery. In both animals and humans with incomplete spinal cord injuries, an appropriately selected operant conditioning protocol can restore more normal locomotion.