Anatomical plasticity and sparing of function after spinal cord damage in neonatal cats.

Spinal cord damage in neonatal cats has different effects on different spinal pathways. Corticospinal projections exhibit anatomical plasticity, forming an aberrant pathway that bypasses the lesion. In contrast, brainstem-spinal pathways undergo massive retrograde degeneration. Neither of these responses occurs in adult cats. Sparing of motor function is found in cats operated on as neonates but not in cats operated on as adults, and appears to depend on the plasticity of the corticospinal tract.