Motor
learning by field approximation
F. GANDOLFO, F.A.MUSSA-IVALDI*, AND E. BIZZI
Department
of Brain and Cognitive Sciences, Massachusetts Institute of Technology,
Cambridge, MA 02139-4307
Proc. Natl.
Acad. Sci. USA
Vol. 93,
pp. 3843–3846, April 1996
Neurobiology
Contributed
by E. Bizzi, January 3, 1996
ABSTRACT
We
investigated how human subjects adapt to forces perturbing the motion of their
arms. We found that this kind of learning is based on the capacity of the
central nervous system (CNS) to predict and therefore to cancel externally
applied perturbing forces. Our experimental results indicate: (i) that
the ability of the CNS to compensate for the perturbing forces is restricted to
those spatial locations where the perturbations have been experienced by the
moving arm. The subjects also are able to compensate for forces experienced at
neighboring workspace locations. However, adaptation decays smoothly and
quickly with distance from the locations where disturbances had been sensed by
the moving limb. (ii) Our experiments also show that the CNS builds an
internal model of the external perturbing forces in intrinsic (muscles and/or
joints) coordinates.