Motor Control Strategies Revealed in the Structure of Motor Variability

  title={Motor Control Strategies Revealed in the Structure of Motor Variability},
  author={Mark L. Latash and John P. Scholz and Gregor Sch{\"o}ner},
  journal={Exercise and Sport Sciences Reviews},
LATASH, M.L., J.P. SCHOLZ, and G. SCHÖNER. Motor control strategies revealed in the structure of motor variability. Exerc. Sport Sci. Rev., Vol. 30, No. 1, pp 26–31, 2002. We describe an uncontrolled manifold hypothesis, which suggests a particular solution for the notorious problem of motor redundancy. A body of recent experiments supports the uncontrolled manifold hypothesis and shows its ability to discover biological strategies of the coordination of apparently redundant motor systems. The… 
Sensory motor remapping of space in human-machine interfaces.
The SURE REACH Model for Motor Learning and Control of a Redundant Arm 87 2 Theories of Motor Learning , Movement Preparation , and Control
The recently introduced neural network SURE REACH (sensorimotor unsupervised redundancy resolving control architecture) models motor cortical learning and control of human reaching movements. The
Hierarchies of Synergies in Human Movements.
This approach offers an operational definition for motor synergies using the framework of the uncontrolled manifold hypothesis, which offers a physiologically based mechanism, which may form the basis for hierarchies of synergies.
Evolution of Motor Control: From Reflexes and Motor Programs to the Equilibrium-Point Hypothesis
  • M. Latash
  • Psychology, Biology
    Journal of human kinetics
  • 2008
This brief review analyzes the evolution of motor control theories along two lines that emphasize active (motor programs) and reactive features of voluntary movements and suggests that the only contemporary hypothesis that integrates both approaches in a fruitful way is the equilibrium-point hypothesis.
Postural Synergies and Their Development
The recent developments of a particular approach to analyzing motor synergies based on the principle of motor abundance has allowed a quantitative assessment of multieffector coordination in motor
Repetition Without Repetition: Challenges in Understanding Behavioral Flexibility in Motor Skill
Examples from sport are used as a context to highlight the factors that are critical to understanding behavioral flexibility, and its connection to movement variability, stability, and learning.
Simplified and effective motor control based on muscle synergies to exploit musculoskeletal dynamics
This study proposes a principle for the design of a low-dimensional controller, that it endeavors to control the natural dynamics of the limb, taking into account the nature of the task being performed.
Exploration of joint redundancy but not task space variability facilitates supervised motor learning
Significance Theories of reinforcement learning claim that motor variability helps in motor learning and are supported by recent experimental work. In contrast, theories of motor control propose that
Motor Synergies and Their Changes with Practice
We review a series of studies that used the framework of the uncontrolled manifold (UCM) hypothesis to quantify changes in motor synergies with practice. The UCM hypothesis states that control of a


On the problem of adequate language in motor control.
Notions of structural units and synergies and the principle of minimal interaction are revisited and Equilibrium-point hypothesis is considered an example of identifying significant variables in the control of a voluntary movement.
What are “normal movements” in atypical populations?
Abstract Redundancy of the motor control system is an important feature that gives the central control structures options for solving everyday motor problems. The choice of particular control
Structure of motor variability in marginally redundant multifinger force production tasks
One subject showed different relations between VUN and VCOMP, suggesting that these relations did in fact reflect particular central strategies of solving the tasks, and the UCM method is applicable to force production tasks.
Structure of joint variability in bimanual pointing tasks
It is concluded that the UCM hypothesis allows quantitative assessment of the degree of stabilization of selected performance variables and provides information on changes in the structure of a multijoint synergy that may not be reflected in its overall performance.
Identifying the control structure of multijoint coordination during pistol shooting
The UCM principle applied to relative gun orientation captures the structure of the motor control system across different parts of joint configuration space as the movement evolves in time, and suggests a specific control strategy in which changes of joint configurations that are irrelevant to success at the task are selectively released from control.
Understanding finger coordination through analysis of the structure of force variability
The results lead to the suggestion that successful task performance is achieved, not by selecting a single optimal solution, but by discovering an appropriate control law that selectively stabilizes certain combinations of degrees of freedom relevant to the task while releasing from control other combinations.
Variability and Motor Control
The text reviews traditional perspectives on movement variability and moves on to consider dynamical systems approaches to movement control, which view variability as an index of movement fluctuations, and reveals how describing and understanding variability can further the knowledge of movement impairment.
Effects of varying task constraints on solutions to joint coordination in a sit-to-stand task
The observed finding of much larger variability in directions of joint space that leave the CM unchanged compared with directions that affect CM position supports the view that the CNS responds to increased task difficulty through enhanced coordination among degrees of freedom.
The uncontrolled manifold concept: identifying control variables for a functional task
An operational meaning to ” controlled” and ”uncontrolled” is given and a method of analysis through which hypotheses about controlled and uncontrolled degrees of freedom can be tested is described, finding that, for the task of sit-to-stand, the position of the center of mass in the sagittal plane was controlled.
Coordination underlying the control of whole body momentum during sit-to-stand.