Joiner WM, Brayanov JB & Smith MA (2013). The training schedule affects the stability, not the magnitude, of the interlimb transfer of learned dynamics.
Journal of Neurophysiology, 110 (to appear).
Abstract:
The way that a
motor adaptation is trained, for example, the manner in which it is
introduced or the duration of the training period, can influence its
internal representation. However, recent studies examining the gradual
versus abrupt introduction of a novel environment have produced
conflicting results. Here we examined how these effects determine the
effector specificity of motor adaptation during visually guided reaching.
After adaptation to velocity-dependent dynamics in the right arm,
we estimated the amount of adaptation transferred to the left arm,
using error-clamp measurement trials to directly measure changes in
learned dynamics. We found that a small but significant amount of
generalization to the untrained arm occurs under three different
training schedules: a short-duration (15 trials) abrupt presentation, a
long-duration (160 trials) abrupt presentation, and a long-duration
gradual presentation of the novel dynamic environment. Remarkably,
we found essentially no difference between the amount of interlimb
generalization when comparing these schedules, with 9–12% transfer
of the trained adaptation for all three. However, the duration of
training had a pronounced effect on the stability of the interlimb
transfer: The transfer elicited from short-duration training decayed
rapidly, whereas the transfer from both long-duration training schedules
was considerably more persistent (<50% vs. >90% retention
over the first 20 trials). These results indicate that the amount of
interlimb transfer is similar for gradual versus abrupt training and that
interlimb transfer of learned dynamics can occur after even a brief
training period but longer training is required for an enduring effect.
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