The bliss (not the problem) of motor abundance (not redundancy)
- 14 January 2012
- journal article
- review article
- Published by Springer Science and Business Media LLC in Experimental Brain Research
- Vol. 217 (1), 1-5
- https://doi.org/10.1007/s00221-012-3000-4
Abstract
Motor control is an area of natural science exploring how the nervous system interacts with other body parts and the environment to produce purposeful, coordinated actions. A central problem of motor control—the problem of motor redundancy—was formulated by Nikolai Bernstein as the problem of elimination of redundant degrees-of-freedom. Traditionally, this problem has been addressed using optimization methods based on a variety of cost functions. This review draws attention to a body of recent findings suggesting that the problem has been formulated incorrectly. An alternative view has been suggested as the principle of abundance, which considers the apparently redundant degrees-of-freedom as useful and even vital for many aspects of motor behavior. Over the past 10 years, dozens of publications have provided support for this view based on the ideas of synergic control, computational apparatus of the uncontrolled manifold hypothesis, and the equilibrium-point (referent configuration) hypothesis. In particular, large amounts of “good variance”—variance in the space of elements that has no effect on the overall performance—have been documented across a variety of natural actions. “Good variance” helps an abundant system to deal with secondary tasks and unexpected perturbations; its amount shows adaptive modulation across a variety of conditions. These data support the view that there is no problem of motor redundancy; there is bliss of motor abundance.Keywords
This publication has 40 references indexed in Scilit:
- Unpredictable elbow joint perturbation during reaching results in multijoint motor equivalenceJournal of Neurophysiology, 2011
- Age-related changes in optimality and motor variability: an example of multifinger redundant tasksExperimental Brain Research, 2011
- Speed-difficulty trade-off in speech: Chinese versus EnglishExperimental Brain Research, 2011
- On strong anticipationCognitive Systems Research, 2010
- Fatigue and Motor Redundancy: Adaptive Increase in Finger Force Variance in Multi-Finger TasksJournal of Neurophysiology, 2010
- An analytical approach to the problem of inverse optimization with additive objective functions: an application to human prehensionJournal of Mathematical Biology, 2009
- Joint coordination during bimanual transport of real and imaginary objectsNeuroscience Letters, 2009
- What Do Synergies Do? Effects of Secondary Constraints on Multidigit Synergies in Accurate Force-Production TasksJournal of Neurophysiology, 2008
- Effect of motor planning on use of motor abundanceNeuroscience Letters, 2007
- The role of kinematic redundancy in adaptation of reachingExperimental Brain Research, 2006