Trends in Cognitive Sciences
Volume 5, Issue 11, 1 November 2001, Pages 487-494
Journal home page for Trends in Cognitive Sciences

Review
Perspectives and problems in motor learning

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Abstract

Movement provides the only means we have to interact with both the world and other people. Such interactions can be hard-wired or learned through experience with the environment. Learning allows us to adapt to a changing physical environment as well as to novel conventions developed by society. Here we review motor learning from a computational perspective, exploring the need for motor learning, what is learned and how it is represented, and the mechanisms of learning. We relate these computational issues to empirical studies on motor learning in humans.

Section snippets

Why do we need motor learning?

Learning involves changes in behaviour that arise from interaction with the environment and is distinct from maturation, which involves changes that occur independent of such interaction. The goal of learning is, in general, to improve performance. Whereas some simple species show no motor learning, the need for motor learning arises in species in which the organism's environment, body or task change. Specifically, when such changes are unpredictable, they cannot be pre-specified in a control

What is learned in motor learning?

From a computational viewpoint the brain is a processing system that converts inputs to outputs. The outputs are the motor commands acting on ensembles of muscles and the inputs are the aggregate of sensory feedback provided by our sense organs and derived internally from an efference copy of the descending motor command. Motor control can be thought of as the process of transforming sensory inputs into consequent motor outputs. The problem of motor learning is one of mastering and adapting

What is the computational basis of motor learning?

There are three principal ways in which the learning system can interact with the environment; these three ways correspond to three computational paradigms for learning: (1) supervised; (2) reinforcement; and (3) unsupervised learning. We consider the motor learning system taking in sensory inputs and producing motor outputs. In supervised learning, the environment provides, for each input, an explicit desired output or target. The goal of the learning system is to learn the mapping from inputs

What makes motor control difficult?

The algorithms discussed in the previous section can in theory be used to learn internal models required for skilled performance. However, there are several features of the human motor system that significantly complicate learning and control. First, there are considerable time delays in both the transduction and transport of sensory signals to the CNS. For example, visual input can take around 100 ms to be processed. When this sensory delay is combined with efferent delays associated with

How is motor learning represented?

In principle, internal models can be represented in motor memory in many different ways. How they are represented in the CNS has important functional implications. The representation determines the coordinate systems of the neurons’ code and what changes to the mapping are easy to learn. We can distinguish between two extremes of representation. Lookup tables simply store the output for each possible setting of the input. Lookup tables are infinitely flexible, but suffer from their inability to

What are the building blocks of motor learning?

Recently, focus has begun to shift away from examining learning of a single internal model to consider how we are able to learn a variety of tasks. Many situations that we encounter are derived from a combination of previously experienced situations, such as novel conjoints of manipulated objects and environments. Internal models can be regarded conceptually as motor primitives, which are the building blocks used to construct intricate motor behaviours with an enormous range. By modulating the

How does motor learning relate to perception and cognition?

As stated at the beginning of this article, direct information transmission between people, such as speech, arm gestures or facial expressions, is mediated through the motor system, which provides a common code for communication. An important idea in psychology is that perception of the action of others, including speech, involves the action system 59. Others’ actions are decoded by activating one's own action system at a subthreshold level and there appear to be special neural mechanism for

Questions for future research

  • What are the common elements of motor learning and other forms of learning? Are the differences between motor and other forms of learning (e.g. perceptual) at a cellular level or a systems level?

  • How are internal models of external objects, such as tools, integrated with the internal models of our own body, such as the arm?

  • What are the characteristics of motor tasks that lead to competition in motor working memory and are there multiple motor working memory systems?

  • Are the internal models that

Acknowledgements

This work was supported by grants from the Wellcome Trust, the Medical Research Council, the BBSRC and the Human Frontier Science Project. Cartoons from CALVIN AND HOBBES © Bill Watterson. Reprinted with permission of Universal Press Syndicate. All rights reserved.

References (66)

  • F.A. Mussa-Ivaldi

    Modular features of motor control and learning

    Curr. Opin. Neurobiol.

    (1999)
  • A.M. Liberman et al.

    On the relation of speech to language

    Trends Cognit. Sci.

    (2000)
  • G. Rizzolatti et al.

    Language within our grasp

    Trends Neurosci.

    (1998)
  • J. Grezes

    Does perception of biological motion rely on specific brain regions?

    NeuroImage

    (2001)
  • S.T. Grafton

    Premotor cortex activation during observation and naming of familiar tools

    NeuroImage

    (1997)
  • I. Eibl-Eibesfeldt

    The expressive behavior of the deaf-and-blind-born

  • R.N. Lemon

    Cortical control of the primate hand. The 1992 GL brown prize lecture

    Exp. Physiol.

    (1993)
  • D.M. Wolpert

    An internal model for sensorimotor integration

    Science

    (1995)
  • J.R. Flanagan et al.

    The role of internal models in motion planning and control: evidence from grip force adjustments during movements of hand-held loads

    J. Neurosci.

    (1997)
  • R.S. Johansson

    Sensory input and control of grip

    Novartis Found. Symp.

    (1998)
  • S.J. Blakemore

    Perceptual modulation of self-produced stimuli: the role of spatio-temporal prediction

    J. Cogn. Neurosci.

    (1999)
  • J.A.S. Kelso

    Dynamic Patterns: The Self-Organization of Brain and Behavior

    (1995)
  • D.E. Rumelhart

    Learning internal representations by back-propagating errors

    Nature

    (1986)
  • R. Sutton et al.

    Reinforcement Learning

    (1998)
  • N. Bernstein

    The Coordination and Regulation of Movements

    (1967)
  • A.E. Bryson et al.

    Applied Optimal Control

    (1975)
  • W.L. Nelson

    Physical principles for economies of skilled movements

    Biol. Cybern.

    (1983)
  • T. Flash et al.

    The co-ordination of arm movements: an experimentally confirmed mathematical model

    J. Neurosci.

    (1985)
  • Y. Uno

    Formation and control of optimal trajectories in human multijoint arm movements: minimum torque-change model

    Biol. Cybern.

    (1989)
  • R.A. Schmidt

    Motor output variability: a theory for the accuracy of rapid motor acts

    Psychol. Rev.

    (1979)
  • C.M. Harris et al.

    Signal-dependent noise determines motor planning

    Nature

    (1998)
  • E. Oja

    A simplified neuron model as a principal component analyzer

    J. Math. Biol.

    (1982)
  • R. Linsker

    From basic network principles to neural architecture: emergence of spatial-opponent cells

    Proc. Natl. Acad. Sci. U. S. A

    (1986)
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