Does the motor control system use multiple models and context switching to cope with a variable environment?

Studies of arm movements have shown that subjects learn to compensate predictable mechanical perturbations by developing a representation of the relation between the state of motion of the arm and the perturbing forces. Here, we tested the hypothesis that subjects construct internal representations...

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Bibliographic Details
Published in:Experimental brain research 2002-04, Vol.143 (4), p.520-524
Main Authors: KARNIEL, A, MUSSA-IVALDI, F. A
Format: Article
Language:English
Subjects:
Adaptation, Psychological - physiology
Adult
Biological and medical sciences
Central Nervous System - physiology
Confidence Intervals
Environment
Female
Fundamental and applied biological sciences. Psychology
Humans
Male
Middle Aged
Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration
Movement - physiology
Psychomotor Performance - physiology
Vertebrates: nervous system and sense organs
Citations: Items that cite this one
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Summary:Studies of arm movements have shown that subjects learn to compensate predictable mechanical perturbations by developing a representation of the relation between the state of motion of the arm and the perturbing forces. Here, we tested the hypothesis that subjects construct internal representations of two different force fields and switch between them when presented with an alternating sequence of these fields. Our results do not support this hypothesis. Subjects performed reaching movements in four sessions over 4 days. On the 1st day the robotic manipulandum perturbed the movement by perpendicular force that alternated its direction after each movement. Subjects were unable to construct the two underlying models and switch between them. On the 2nd day only one field was applied and well learned. On the 3rd day only the other field was applied and well learned. Then the experiment of the 1st day was repeated on the 4th day. Even after this extensive training subjects showed no signs of improved performance with alternating fields. This result combined with previous studies suggests that the central nervous system has a strong tendency to employ a single internal model when dealing with a sequence of perturbations.
ISSN:0014-4819
1432-1106
DOI:10.1007/s00221-002-1054-4