Differential recovery of bipedal and overground locomotion following complete spinal cord hemisection in cats.

We used behavioral assessment techniques to investigate the recovery of locomotion after spinal cord injury. Complete hemisec-tions were made at T13 and LI in the cat spinal cord. Observational and high-speed kinematic analyses of bipedal treadmill and overground locomotion were made from 1 to 5 weeks postoperatively. Both bipedal and overground locomotion showed partial recovery. The early stage of recovery was characterized by an increased range of joint movement in a proximal to distal progression. During later stages, hindlimb movements became more complex and interjoint coordination markedly improved. Overground locomotion recovered faster and to a greater extent than bipedal locomotion, as indicated by the time course of recovery, joint angular excursions and intralimb coordination. We propose that the recovery of bipedal locomotion may be more limited by reorganization of segmenta) sensory systems than overground locomotion, perhaps because alternate strategies for overground locomotion are available.