Operation of spinal sensorimotor circuits controlling phase durations during tied-belt and split-belt locomotion after a lateral thoracic hemisection

This study investigates how spinal cord injuries affect the control of walking. Specifically, it examines the impact of a hemisection (cutting half the spinal cord) on walking patterns in cats during tied-belt and split-belt treadmill exercises. The researchers used a computer model to simulate the effects of the hemisection. The model predicted changes in the timing of steps and leg movements, which were then compared with actual experimental results from cats with hemisections. The study found that the model's predictions were generally consistent with the experimental results. This suggests that the model accurately captures some key aspects of how the spinal cord controls walking after an injury, particularly how sensory feedback and brain signals interact.

• 1
  During tied-belt locomotion, the contralesional hindlimb's speed-dependent changes were similar to intact conditions, while the ipsilesional hindlimb showed shorter stance and longer swing phases.
• 2
  During split-belt locomotion with the ipsilesional hindlimb on the fast belt, the contralesional hindlimb had increased cycle and stance durations, while the ipsilesional hindlimb showed decreased stance and increased swing phases, leading to a duty factor below 50%.
• 3
  During split-belt locomotion with the ipsilesional hindlimb on the slow belt, changes in cycle and phase durations in both hindlimbs were similar to those of intact cats, suggesting reduced limping.