Following a C4/5 right over-hemisection injury rats have significant locomotor deficits. In the weeks following injury, spontaneous recovery of function occurs. However, in addition to the recovery, some behaviors that were initially normal after injury become abnormal a few weeks later. Our data suggests that the less impaired limbs develop compensatory techniques which enable the more impaired limbs to take more normal steps.

Our robotic gait training techniques aim to improve upon this spontaneous recovery by minimizing both the functional deficits as well as the development of compensatory techniques. Currently we are finding that actively guiding rats through a symmetric pre-injury pattern accomplishes this. And not just in the robotic device, but walking overground in the CatWalk®. Through our MRI techniques we have also found evidence that our training induces neuronal plasticity at the injury site, but not in the red nucleus. Suggesting that it is new connections, and not the spared pathways, that are enabling the functional recovery we observe.

We are continuing to investigate the ability of guiding through asymmetric exaggerated patterns, as well as training within positive/negative viscosity fields to improve upon this functional recovery. These findings can easily be applied to the clinic by reprogramming robotic gait trainers such as the Lokomat®.