Document Detail

Motor adaptation as a process of reoptimization.
MedLine Citation:
PMID:  18337419     Owner:  NLM     Status:  MEDLINE    
Adaptation is sometimes viewed as a process in which the nervous system learns to predict and cancel effects of a novel environment, returning movements to near baseline (unperturbed) conditions. An alternate view is that cancellation is not the goal of adaptation. Rather, the goal is to maximize performance in that environment. If performance criteria are well defined, theory allows one to predict the reoptimized trajectory. For example, if velocity-dependent forces perturb the hand perpendicular to the direction of a reaching movement, the best reach plan is not a straight line but a curved path that appears to overcompensate for the forces. If this environment is stochastic (changing from trial to trial), the reoptimized plan should take into account this uncertainty, removing the overcompensation. If the stochastic environment is zero-mean, peak velocities should increase to allow for more time to approach the target. Finally, if one is reaching through a via-point, the optimum plan in a zero-mean deterministic environment is a smooth movement but in a zero-mean stochastic environment is a segmented movement. We observed all of these tendencies in how people adapt to novel environments. Therefore, motor control in a novel environment is not a process of perturbation cancellation. Rather, the process resembles reoptimization: through practice in the novel environment, we learn internal models that predict sensory consequences of motor commands. Through reward-based optimization, we use the internal model to search for a better movement plan to minimize implicit motor costs and maximize rewards.
Jun Izawa; Tushar Rane; Opher Donchin; Reza Shadmehr
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  28     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2008 Mar 
Date Detail:
Created Date:  2008-03-13     Completed Date:  2008-04-08     Revised Date:  2014-09-20    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2883-91     Citation Subset:  IM    
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MeSH Terms
Adaptation, Physiological / physiology*
Motor Skills / physiology*
Psychomotor Performance / physiology*
Reaction Time / physiology
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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