Neural circuits that control walking in humans are highly adaptable, according to research using split-belt treadmills. Not only can they compensate for one belt moving faster than the other, they also allow us to learn how to walk when the belts are traveling in different directions.
This research, published in Nature Neuroscience, indicates that cerebral stroke victims and epileptic children with hemispherectomies (removal of half the brain) who walk with a limp may one day be able to eliminate the limp with training.
These findings led Kennedy Krieger Institute researchers Amy Bastian and Julia Choi to conclude that unique neural control circuits exist for each leg to deal with speed. Known as hybrid walking, the last and most unique of the findings demonstrate that another set exists for handling direction in each leg.
The new evidence overturns the previous assumption, where a single locomotor circuit (believed to be a central pattern generator; CPG) regulated the movement of both legs simultaneously.
Bastian's previous research has shown that the "little brain," or cerebellum, is necessary to help learn "predictive movements" necessary to counteract the limping. The current hypothesis seems to be that the CPG controls walking while the cerebellum assists in boosting the efficiency of its learning.
