Locomotor adaptation to support surface perturbations is characterized by environmental decoupling
Advisor Information
Mukul Mukherjee
Location
Dr. C.C. and Mabel L. Criss Library
Presentation Type
Poster
Start Date
6-3-2015 9:00 AM
End Date
6-3-2015 10:30 AM
Abstract
Human locomotor adaptation requires control processes driven by sensory feedback to maintain dynamic stability in response to environmental perturbations. Effective postural adaptation is characterized by a decoupling of the environmental perturbation and movements of the trunk. Maladaptive adaptation in conditions of inaccurate sensory input may lead to postural instability. In this study we investigated locomotor adaptation to a continuously rolling treadmill. While walking on the treadmill, 20 participants performed a locomotor adaptation, consisting of baseline, adaptation (sinusoidal roll: ± 5°), catch, retention and transfer trials. Learning was quantified as a decoupling of mediolateral treadmill and trunk roll, computed as the cross-correlation function (XCF) between treadmill and trunk motion. Analysis revealed a trend of decoupling over consecutive trials. Decoupling is primarily observed in the learning phase, indicated by a systematic reduction in XCF in treadmill – trunk (p<0.01) coupling. The learnt sinusoidal roll dynamics transfer to a randomized rolling treadmill (p<0.05). As learning environmental dynamics occurs, over time a stable decoupled state is achieved and maintained. Significant transfer of decoupling behaviour to the random perturbation, suggests sensory reorganization as the driving phenomenon. Increased reliance on visual information to encode physical orientation, as opposed to lower-limb proprioceptive signals allows suprapelvic body segments to be controlled using sensory feedback from more stable sources in the environment. Over time this allows for the minimization of mechanical environmental influences.
Locomotor adaptation to support surface perturbations is characterized by environmental decoupling
Dr. C.C. and Mabel L. Criss Library
Human locomotor adaptation requires control processes driven by sensory feedback to maintain dynamic stability in response to environmental perturbations. Effective postural adaptation is characterized by a decoupling of the environmental perturbation and movements of the trunk. Maladaptive adaptation in conditions of inaccurate sensory input may lead to postural instability. In this study we investigated locomotor adaptation to a continuously rolling treadmill. While walking on the treadmill, 20 participants performed a locomotor adaptation, consisting of baseline, adaptation (sinusoidal roll: ± 5°), catch, retention and transfer trials. Learning was quantified as a decoupling of mediolateral treadmill and trunk roll, computed as the cross-correlation function (XCF) between treadmill and trunk motion. Analysis revealed a trend of decoupling over consecutive trials. Decoupling is primarily observed in the learning phase, indicated by a systematic reduction in XCF in treadmill – trunk (p<0.01) coupling. The learnt sinusoidal roll dynamics transfer to a randomized rolling treadmill (p<0.05). As learning environmental dynamics occurs, over time a stable decoupled state is achieved and maintained. Significant transfer of decoupling behaviour to the random perturbation, suggests sensory reorganization as the driving phenomenon. Increased reliance on visual information to encode physical orientation, as opposed to lower-limb proprioceptive signals allows suprapelvic body segments to be controlled using sensory feedback from more stable sources in the environment. Over time this allows for the minimization of mechanical environmental influences.