"Using Locomotor Adaptation to Uncover Sensorimotor Control Principles during Human Locomotion"

James Finley, PhD
Division of Biokinesiology and Physical Therapy
University of Southern California

Abstract:
Walking is one of the primary ways in which we move through our environment, and as a result of development and experience, we acquire the ability to seamlessly transition between tasks such as walking on pavement to walking on soft sand to walking on an icy sidewalk to crossing a stream via stepping stones. Learning to switch between these types of environments requires the nervous system to adapt the calibrations used for one context to produce the appropriate motor commands for another. This process of locomotor adaptation is critical for normal behavior and may also underlie the processes by which the neuromuscular system adapts to damage of central or peripheral motor structures. My recent research has focused on understanding the factors involved in the adaptive control of locomotion in the context of learning to walk on a split-belt treadmill. When naive individuals are exposed to walking on this device, they walk with steps of unequal length (asymmetry), but over time adapt to produce steps of equal length (symmetry). I will first demonstrate that the reduction in asymmetry during adaptation is associated with a reduction in muscle activity and metabolic cost. These findings provide evidence that locomotor adaptation may be driven by an energetic optimization process. In addition to exploring the role of energetics during locomotor learning, my work has also demonstrated that learning can be accelerated by imposing novel patterns of optic flow during split-belt adaptation. This leads to the exciting possibility that intelligent use of augmented reality may be able to promote learning and rehabilitation. I will conclude by sharing recent findings which provide insight into how the asymmetric walking patterns commonly observed following stroke contribute to the increased energetic cost of walking in these individuals.

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