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dc.contributor.advisorJeka, John Jen_US
dc.contributor.authorLogan, David Michaelen_US
dc.date.accessioned2015-02-07T06:33:26Z
dc.date.available2015-02-07T06:33:26Z
dc.date.issued2014en_US
dc.identifierhttps://doi.org/10.13016/M20P6T
dc.identifier.urihttp://hdl.handle.net/1903/16269
dc.description.abstractMaintenance of upright posture during walking is one the most important tasks to ensure flexible and stable mobility, along with speed adjustment, wayfinding and obstacle avoidance. These underlying functions, or subtasks, are simultaneously coordinated by the nervous system, which relies heavily on sensory feedback to obtain continual estimates of self-motion. This dissertation reports the findings of four experiments which made use of visual and mechanical perturbations to probe the interplay of these subtasks during treadmill walking. To confront the inherent nonlinearity of human gait, novel frequency domain analyses and impulse response functions that take into account phase of the gait cycle were used to characterize perturbation-response relationships. In the first experiment, transient visual scene motion was used to probe how visual input simultaneously influenced multiple subtasks, but at different phases of the gait cycle. In the second experiment, kinematics and muscle activity response variables showed an amplitude dependency on visual scene motion during walking that indicates vision is reweighted in a manner similar to standing posture. The third experiment used a metronome to constrain walking, revealing two time scales of locomotive control. The final experiment made use of both visual and mechanical perturbations simultaneously to probe the subtasks of postural orientation upright and positional maintenance on the treadmill. Doing so revealed that the nervous system prioritizes control of postural orientation over positional maintenance. In sum, this dissertation shows that sensory and mechanical perturbations provide insight as to how the nervous system controls coexisting, underlying functions during walking.en_US
dc.language.isoenen_US
dc.titleSubtask Control in Human Locomotionen_US
dc.typeDissertationen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.contributor.departmentNeuroscience and Cognitive Scienceen_US
dc.subject.pqcontrolledNeurosciencesen_US
dc.subject.pqcontrolledKinesiologyen_US
dc.subject.pquncontrolledgaiten_US
dc.subject.pquncontrolledLocomotionen_US
dc.subject.pquncontrolledmotor controlen_US
dc.subject.pquncontrolledsensorimotoren_US
dc.subject.pquncontrolledvisionen_US
dc.subject.pquncontrolledwalkingen_US


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