Activity-dependent plasticity: implications for recovery after spinal cord injury.

Spinal cord injury causes devastating loss of function and progressive, potentially life-threatening, secondary complications. Although significant preclinical advances continue to be made in cellular and molecular therapies which promote regeneration, plasticity within remaining circuits and how it can be influenced by physical activity is evolving as a key research area. Understanding what constitutes plasticity, and how activity shapes it, has centred primarily on neurons, but evidence is emerging that activity also influences glial cells. Basic and clinical research continue to advance our knowledge of the quality and quantity of physical exercise required to improve function, while mental exercise is emerging as another avenue. Increased understanding of mechanisms driving activity-dependent plasticity will help develop rehabilitative strategies which optimise functional recovery.