Human Locomotor Plasticity in Health and Disease

Principal Investigator: Amy Bastian

Sponsored by the National Institutes of Health -- 5R01HD048741-06.

Walking patterns can adapt on short timescales (minutes to hours) to temporary conditions, such as icy sidewalks. They can also adapt on long timescales (months to years) to permanent conditions produced by growth or damage. Walking deficits occur when long-term learning to compensate for damage is absent or inappropriate. We recently discovered that the walking deficits in people with hemiparesis can be improved on short timescales by adaptation to split-belt treadmill conditions that exaggerate the deficit. The exaggeration drives the nervous system to adapt to correct the deficit, and results in improved walking patterns when the person returns to normal conditions. Here, we plan to investigate how short-term adaptation can be translated into long-term improvement in walking patterns.

Transfer of short-term walking adaptations to long-term learning of walking patterns has not been studied previously. However, research on other learning paradigms suggests that long-term improvements will depend critically on training conditions and learning schedule. Therefore, in Aim 1, we ask whether walking adaptation and generalization depend on training conditions. We hypothesize that generalization can be enhanced through the use of congruent visual cues during training on the split-belt treadmill, and that generalization is modulated by the level of conscious effort during training.

In Aim 2, we ask how long-term walking improvements depend on learning schedules. We hypothesize that the day-to-day retention of a new walking pattern depends on the intervening activity of the trainee, and that learning depends on the temporal structure of the training schedule. All experiments in Aims 1 and 2 will be tested in adults and children.

In Aim 3, we put what we learn into practice with a pilot clinical trial in children with hemiparesis. Overall, these studies will uncover fundamental principles that affect long-term motor learning processes, and are critical for developing rational, evidence-based rehabilitation practices.