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Earlier studies have suggested that coordination is driven by the
goal of achieving simple and regular movements of an
“endpoint” in space. For example, the central nervous system (CNS)
coordinates in time the motions of shoulder and elbow so as to achieve
simple rectilinear motions of the hand. Other studies have suggested that
the control of hand movement direction and amplitude are mutually
independent. Now, we seek to understand how these mechanisms for
coordination may be remapped when the relation between the motor commands
and the motions of the endpoint is radically altered. We have developed a
simple experimental paradigm where finger postures obtained by a data glove
are arbitrarily transformed to define the 2D location of an endpoint—a cursor on a computer screen. Subjects are
then asked to execute specific movements of this endpoint by learning
appropriate finger motions. We will address three main questions: 1) what
features of the endpoint behavior guide the reorganization of coordinated
movements? 2) How is this reorganization reflected by the distribution of
activities across brain regions? and 3) Can we
design paradigms for training coordination that capitalize on the
reorganization capacities to obtain simple and regular motions of a
controlled endpoint? By addressing these studies in three sets of
investigations, we hope to gain new knowledge on how space is represented
in the sensory-motor system.
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