Prediction Precedes Control in Motor Learning

Abstract

Skilled motor behavior relies on the brain learning both to control the body and predict the consequences of this control. Prediction turns motor commands into expected sensory consequences, whereas control turns desired consequences into motor commands. To capture this symmetry, the neural processes underlying prediction and control are termed the forward and inverse internal models, respectively. Here, we investigate how these two fundamental processes are related during motor learning. We used an object manipulation task in which subjects learned to move a hand-held object with novel dynamic properties along a prescribed path. We independently and simultaneously measured subjects' ability to control their actions and to predict their consequences. We found different time courses for predictor and controller learning, with prediction being learned far more rapidly than control. In early stages of manipulating the object, subjects could predict the consequences of their actions, as measured by the grip force they used to grasp the object, but could not generate appropriate actions for control, as measured by their hand trajectory. As predicted by several recent theoretical models of sensorimotor control, our results indicate that people can learn to predict the consequences of their actions before they can learn to control their actions.

Evidence for a distributed hierarchy of action representation in the brain

“…Prediction is readily observed in prehension tasks, where the eyes lead the hand in locating goal targets Mennie, Hayhoe, & Sullivan, 2006). It has been shown in learning studies that prediction emerges faster than control (Flanagan, Vetter, Johansson, & Wolpert, 2003). The idea of predictive forward models has also been incorporated into a more sophisticated computational framework, where a system of multiple parallel forward -inverse model pairs are able to provide accurate control of action in a variety of contexts, in a model called MOSAIC (Wolpert & Kawato, 1998).…”

A comparison of motor imagery performance in children with spastic hemiplegia and developmental coordination disorder

“…It is thought to be a copy of a movement plan coming to consciousness because actual movement has been inhibited (Crammond, 1997) and may be used to predict the outcome of a particular movement. The ability to predict the outcome of movements is considered to be a crucial part of movement planning and also in the ability to accurately utilise internal models of motor control (Blakemore, Wolpert, & Frith, 2002;Flanagan, Vetter, Johansson, & Wolpert, 2003).…”

Learning modular and transferable forward models of the motions of push manipulated objects

“…The human motor system uses predictive (or forward) models of the effects that motor actions have on sensory state (Flanagan et al 2003(Flanagan et al , 2006Mehta and Schaal 2002;Witney et al 2000;Johansson and Cole 1992). The predictions are used for a variety of purposes, including feedforward control, coordination of motor systems, action planning, and monitoring of action plan execution.…”

“…Prediction of the effects of motor actions has long been studied in neuroscience (Miall and Wolpert 1996;Flanagan et al 2003). MOSAIC was an early computational model of prediction and control in the cerebellum using a modular scheme (Haruno et al 2001), where predictions can be made by convex combinations of learned predictors.…”