Prediction of the body rotation-induced torques on the arm during reaching movements: Evidence from a proprioceptively deafferented subject
Neuropsychologia. 2011-06-01; 49(7): 2055-2059
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Guillaud E(1), Simoneau M, Blouin J.
(1)Faculty of Medicine, Division of Kinesiology, Laval University, Quebec,Canada.
Reaching for a target while rotating the trunk generates substantial Coriolis and
centrifugal torques that push the arm in the opposite direction of the rotations.
These torques rarely perturb movement accuracy, suggesting that they are
compensated for during the movement. Here we tested whether signals generated
during body motion (e.g., vestibular) can be used to predict the torques induced
by the body rotation and to modify the motor commands accordingly. We asked a
deafferented subject to reach for a memorized visual target in darkness. At the
onset of the reaching, the patient was rotated 25° or 40° in the clockwise or the
counterclockwise directions. During the rotation, the patient’s head remained
either fixed in space (Head-Fixed condition) or fixed on the trunk (Head Rotation
condition). At the rotation onset, the deafferented patient’s hand largely
deviated from the mid-sagittal plane in both conditions. The hand deviations were
compensated for in the Head Rotation condition only. These results highlight the
computational faculty of the brain and show that body rotation-related
information can be processed for predicting the consequence of the rotation
dynamics on the reaching arm movements.
Copyright © 2011 Elsevier Ltd. All rights reserved.