Remapping Hand Movements in a Novel Geometrical Environment
J Neurophysiol (September 7, 2005). doi:10.1152/jn.00380.2005
Submitted on April 14, 2005
Accepted on August 28, 2005
1 Kristine M. Mosier, 2 Robert A Scheidt, 3 Santiago Acosta, 3,4 Ferdinando A. Mussa-Ivaldi
1 Indiana University School of Medicine, Department of Radiology, 950 W. Walnut St. R2 E124, Indianapolis, Indiana 46202
2 Marquette University, Department of Biomedical Engineering, P.O. Box 1881, Milwaukee, Wisconsin, 53201
3 Rehabilitation Institute of Chicago, Sensory Motor Performance Program, 345 E. Superior St., Chicago, Illinois 60611
4 Northwestern University, Feinberg School of Medicine, Department of Physiology, (M211) 303 East Chicago Ave, Chicago, Illinois 60611
Running head: Remapping Movement in a Novel Geometrical Environment
Correspondence should be addressed to F.A.M-I (
sandro@northwestern.edu)Remapping in a Novel Geometrical Environment 2
Abstract
The issue of how the Euclidean properties of space are represented in the nervous system is a main focus in the study of visual perception, but is equally relevant to motor learning. The goal of our experiments was to investigate how the properties of space guide the remapping of motor coordination. Subjects wore an instrumented data glove that recorded the finger motions. Signals generated by the glove operated a remotely-controlled endpoint: a cursor on a computer monitor. The subjects were instructed to execute movements of this endpoint with controlled motions of the fingers. This required inverting a highly redundant map from fingers to cursor motions. We found that 1) after training with visual feedback of the final error (but not of the ongoing cursor motion), subjects learned to map cursor locations into configurations of the fingers; 2) extended practice of movement led to more rectilinear cursor movement, a trend facilitated by training under continuous visual feedback of cursor motions; 3) with practice, subjects reduced motion in the degrees of freedom that did not contribute to the movements of the cursor; 4) with practice, subjects reduced variability of both cursor and hand movements; and 5) the reduction of errors and the increase in linearity generalized beyond the set of movements used for training. These findings suggest that subjects not only learned to produce novel coordinated movement to control the placement of the cursor, but they also developed a representation of the Euclidean space upon which hand movements were remapped.