Figure 1.

Left, Schematic representation of a spinal lesion together with some descending pathways originating from the telencephalon or the brainstem. Some axons are lesioned, and others are intact although they could be demyelinated. Below the lesion, a CGP for locomotion interacts with descending inputs and peripheral afferents originating from a lower limb. Middle, Endogenous processes lead to sprouting of descending fibers but little axonal growth through the glial scar. Autonomous spinal functions return to a certain degree. Right, Various exogenous interventions enhance or diminish some mechanisms that may help regeneration or sprouting. Cellular replacement may also favor beneficial immunological processes or foster remyelination. Rehabilitation such as treadmill training can accelerate and stabilize locomotor performance.