Behavioral and Neurophysiologic Process of Locomotor Learning After Stroke
PROJECT SUMMARY / ABSTRACT Despite significant time and money spent on post-stroke rehabilitation, stroke survivors are left with reduced walking capacity and significant disability. Rehabilitation following stroke is required to make gains in walking beyond those achieved through spontaneous recovery during the first several months after stroke and this occurs through relearning movements that have been disrupted due to damage to the brain. Enhancing post- stroke motor learning is therefore critical to improving post-stroke rehabilitation. Most research examining the effects of stroke on locomotor learning has focused on a specific form of implicit locomotor learning (sensorimotor adaptation), which is relatively automatic. Post-stroke rehabilitation, however, is dominated by techniques, such as visual feedback and verbal cues, that are meant to encourage patients? use of explicit learning (requiring attention, awareness). Considering that the effects of stroke on these two categories of learning (explicit and implicit) are likely quite different, since different brain areas are primarily involved in each type of learning, we must understand the effects of stroke on both types of learning. Moreover, factors such as cognitive deficits likely have differing effects, depending on the type of learning. Cognitive function is thought to be critical for more explicit forms of motor learning (specifically strategy-based learning), unlike implicit learning which is thought to place less demand on cognitive resources. Despite the numerous cognitive deficits present after stroke, the influence of cognitive function on motor learning (both implicit and explicit) after stroke has largely been ignored. Finally, differences in explicit and implicit learning may also influence the effects of exercise priming, (the coupling of a short bout of high intensity exercise with a learning task), that has been suggested as a mechanism to enhance motor learning in rehabilitation. In Aims 1 and 2 of this project, using both behavioral and computational data, we will determine the relationship between cognitive deficits (and other factors, such as stroke location) and locomotor learning in both explicit (strategy-based) and implicit (sensorimotor adaptation) locomotor learning tasks in those with chronic (>6 months) stroke. In Aim 3 we examine the effect of a short bout of high intensity exercise immediately following strategy-based locomotor learning on the retention of the newly learned walking pattern, along with its interaction with cognitive deficits, in those with chronic stroke. The results of this proposal have immediate implications for clinical practice because they will inform clinicians when to use certain techniques (e.g.-visual feedback with explicit cues, exercise priming) in patients with stroke with particular cognitive deficits, allowing for the design of personalized rehabilitation interventions.