nips nips2002 nips2002-9 nips2002-9-reference knowledge-graph by maker-knowledge-mining
Source: pdf
Author: Emanuel Todorov, Michael I. Jordan
Abstract: Behavioral goals are achieved reliably and repeatedly with movements rarely reproducible in their detail. Here we offer an explanation: we show that not only are variability and goal achievement compatible, but indeed that allowing variability in redundant dimensions is the optimal control strategy in the face of uncertainty. The optimal feedback control laws for typical motor tasks obey a “minimal intervention” principle: deviations from the average trajectory are only corrected when they interfere with the task goals. The resulting behavior exhibits task-constrained variability, as well as synergetic coupling among actuators—which is another unexplained empirical phenomenon.
[1] Bernstein, N.I. The Coordination and Regulation of Movements. Pergamon Press, (1967).
[2] Bizzi, E., Accornero, N., Chapple, W. & Hogan, N. Posture control and trajectory formation during arm movement. J Neurosci 4, 2738-44 (1984).
[3] Cole, K.J. & Abbs, J.H. Kinematic and electromyographic responses to perturbation of a rapid grasp. J Neurophysiol 57, 1498-510 (1987).
[4] D’Avella, A. & Bizzi, E. Low dimensionality of supraspinally induced force fields. PNAS 95, 7711-7714 (1998).
[5] Davis, M.H.A. & Vinter, R. Stochastic Modelling and Control. Chapman and Hall, (1985).
[6] Domkin D., Laczko, J., Jaric, S., Johansson, H., & Latash, M. Structure of joint variability in bimanual pointing tasks. Exp Brain Res 143, 11-23 (2002).
[7] Fleming, W. and Soner, H. (1993). Controlled Markov Processes and Viscosity Solutions. Applications of Mathematics, Springer-Verlag, Berlin.
[8] Flash, T. & Hogan, N. The coordination of arm movements: an experimentally confirmed mathematical model. J Neuroscience 5, 1688-1703 (1985).
[9] Gelfand, I., Gurfinkel, V., Tsetlin, M. & Shik, M. In Models of the structuralfunctional organization of certain biological systems. Gelfand, I., Gurfinkel, V., Fomin, S. & Tsetlin, M. (eds.) MIT Press, 1971.
[10] Harris, C.M. & Wolpert, D.M. Signal-dependent noise determines motor planning. Nature 394, 780-784 (1998).
[11] Hinton, G.E. Parallel computations for controlling an arm. Journal of Motor Behavior 16, 171-194 (1984).
[12] Robertson, E.M. & Miall, R.C. Multi-joint limbs permit a flexible response to unpredictable events. Exp Brain Res 117, 148-52 (1997).
[13] Sutton, G.G. & Sykes, K. The variation of hand tremor with force in healthy subjects. Journal of Physiology 191(3), 699-711 (1967).
[14] Todorov, E. & Jordan, M. Optimal feedback control as a theory of motor coordination. Nature Neuroscience, 5(11), 1226-1235 (2002).
[15] Todorov, E. Optimal feedback control under signal-dependent noise: Methodology for modeling biological movement. Neural Computation, under review. Available at http://cogsci.ucsd.edu/˜todorov. (2002).
[16] Scholz, J.P. & Schoner, G. The uncontrolled manifold concept: Identifying control variables for a functional task. Exp Brain Res 126, 289-306 (1999).
[17] Uno, Y., Kawato, M. & Suzuki, R. Formation and control of optimal trajectory in human multijoint arm movement: Minimum torque-change model. Biological Cybernetics 61, 89-101 (1989).
[18] Santello, M. & Soechting, J.F. Force synergies for multifingered grasping. Exp Brain Res 133, 457-67 (2000).