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| Record Number | 1985 |
| Reference Type | Conference Proceedings |
| Author(s) | Mohajerian, P.;Mistry, M.;Schaal, S. |
| Year | 2004 |
| Title | Neuronal or spinal level interaction between rhythmic and discrete motion during multi-joint arm movement |
| Journal/Conference/Book Title | Abstracts of the 34st Meeting of the Society of Neuroscience |
| Keywords | movement primitives
behaviors
dynamic systems
computational motor control
discrete
rhythmic
trajectory planning |
Abstract |
This study investigates the interaction of discrete and rhythmic movements when both elements co-occur in the movement of a single limb. The goal of our research is to determine whether such interactions take place, and if yes, whether the interaction happens at a higher neuronal (i.e., planning) or a lower muscular/spinal (i.e., execution) level. In previous studies of single-joint movement tasks, it was reported that the initiation of a discrete movement superimposed to an on-going rhythmic movement is constrained to a particular phase window of the ongoing rhythmic movement. Similarly, interaction was found in a two-joint task consisting of an elbow oscillation in the plane that was to be merged with a fast discrete adduction or abduction of the shoulder.
As previous experiments employed combinations of degrees-of-freedom (DOFs) for discrete and rhythmic movement that had significant overlap in the muscles that contributed to the different motor behaviors, we hypothesized that the observed interactions may be due to spinal interneuronal interference during a superposition of two movement primitives. We conducted a more extensive series of experiments in the unconstraint 7 DOF arm, deploying six different combinations of discrete and rhythmic movements across the 7 DOFs. The primary measure of interaction was whether the discrete movement onset was constraint to a particular phase of the on-going rhythmic movement. Evidence for an interaction at the higher neuronal level should show such phase constraints regardless of which joints contribute to the discrete and rhythmic movements.
Our results demonstrate that the amount of phase constraints significantly varied depending on the joint combination: if the discrete movement required the same muscles as the rhythmic movement, interaction occurredÑotherwise, there was no interaction. We therefore hypothesize that rhythmic and discrete movement are planned separately at a higher level of the CNS, and that the superposition of these plans can cause interaction effects at the spinal/muscular level if a muscle required by the superimposed movement is currently inhibited by the spinal interneuronal circuits.
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| Place Published | San Diego, CA, Oct.23-27 |
| Short Title | Neuronal or spinal level interaction between rhythmic and discrete motion during multi-joint arm movement |
| Papers are available as Adobe PDF ".pdf" files. Adobe Reader is available for free for all computer platforms.
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Page last modified on August 10, 2006, at 06:47 PM
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