New Study from Spaulding Motion Analysis Lab Uses Robots to Attempt to Uncover the Connections Between the Human Mind and Gait Controls
(Boston, MA) - A group based at the Motion Analysis Laboratory at Spaulding Rehabilitation Hospital in conjunction with the Wyss Institute for Biologically Inspired Engineering at Harvard University has published a study entitled “Robot-Driven Locomotor Perturbations Reveal Synergy-Mediated, Context-Dependent Feedforward and Feedback Mechanisms of Adaptation” in the newest issue of Scientific Reports. Researchers used a robot to investigate the roles of feedforward mechanisms controlled by the cerebellum and feedback mechanisms controlled at the spinal level in determining how the nervous system responds to robot-induced changes in step length.
Paolo Bonato, PhD, Director of the Spaulding Motion Analysis Lab, was the lead author on the study. “Our understanding of the neural mechanisms underlying locomotor adaptation is still limited. Specifically, how behavioral, functional and physiological processes work in concert to achieve adaptation during locomotion has remained elusive to date. Our goal is to create a better understanding of this process and hence develop more effective clinical interventions,” said Dr. Bonato.
For the study, the team used a robot to induce two opposite unilateral mechanical perturbations affecting the step length over multiple gait cycles. Electrical signals recorded from muscles (called electromyographic signals) were collected and analyzed to determine how muscle synergies change in response to perturbation. The results demonstrated different bilateral modulation dynamics of the muscle-synergy activations during adaptation, characterized by the combination of feedforward control signals coming from the cerebellum and feedback-driven control signals arising in the spinal cord. The relative side-specific contributions of the two processes to motor-output adjustments, however, depended on which perturbation was delivered. Overall, the observations provide evidence that, in humans, both descending and afferent drives project onto the same spinal interneuronal networks that encode locomotor muscle synergies.
These results strongly suggest the presence, in humans, of a defined population of spinal interneurons regulating muscle coordination that can be accessed by both cortical and afferent drives, as observed in animal models. “Our team hopes to build on this work to develop new approaches to the design of robot-assisted gait rehabilitation procedures targeting specific descending- and afferent-driven responses in muscle synergies in the coming year,” said Bonato.
Individuals can learn more about the Motion Analysis Laboratory at Spaulding Rehabilitation Hospital.
About Spaulding Rehabilitation Network
A member of Partners HealthCare, the Spaulding Rehabilitation Network includes Spaulding Rehabilitation Hospital, with a main campus in Charlestown the 3rd ranked rehabilitation hospital in the country by U.S. News & World Report, along with Spaulding Rehabilitation Hospital Cape Cod, Spaulding Hospital Cambridge, Spaulding Nursing and Therapy Center Brighton, and 25 outpatient sites throughout Eastern Massachusetts. An acclaimed teaching hospital of Harvard Medical School and home to the Department of Physical Medicine and Rehabilitation, Spaulding is recognized as the top residency program in the U.S. in the 2019/2020 Doximity Residency Navigator. Spaulding also was recognized by the 2019 Disability Equality Index as a “Best Places to Work for Disability Inclusion.” For more information, visit www.spauldingrehab.org.
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