Chapter 30 Failure Analysis of Stepping in Adult Spinal Cats

Abstract

Adult cats that receive complete spinal cord transections can regain the ability to perform bipedal hind-limb locomotion on a treadmill. Furthermore, locomotor recovery is enhanced by daily training of the hind limbs on a motorized treadmill. Spinal cats that do not receive treadmill training recover poor locomotor ability relative to the step-trained spinal cats. Nontrained spinal cats stumble frequently and are thus unable to maintain long stepping sequences. The importance of inter-limb coordination in the successful execution of stepping in spinal cats has not been examined thoroughly. Forssberg and colleagues reported that the hind-limb coordination patterns in cats transected at one or two weeks of age resembled that found in normal animals. This chapter discusses whether the patterns of hind-limb coordination during locomotion in adult cats are altered after the cats received a complete low-thoracic spinal cord transection. In addition, to determine if training improved stepping in spinal cats by normalizing hind-limb coordination, stepping is compared before and after spinalization in spinal cats that received treadmill training and in spinal cats that received no training after spinalization. The current findings demonstrate that abnormal patterns of hind-limb coordination are a major cause of step failures—that is, stumbling during stepping in spinal cats. Treadmill training improved hind-limb coordination sufficiently to maintain successful stepping, but did not restore the pre-spinal pattern of hind-limb coordination.