| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
The Journal of Neurophysiology Vol. 88 No. 3 September 2002, pp. 1533-1544
Copyright ©2002 by the American Physiological Society
Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, Queen Square London, WC1N 3BG, United Kingdom
Jones, Kelvin E.,
Antonia F. de
C. Hamilton, and
Daniel M. Wolpert.
Sources of Signal-Dependent Noise During Isometric
Force Production. J. Neurophysiol. 88: 1533-1544, 2002. It has been proposed that the invariant
kinematics observed during goal-directed movements result from reducing
the consequences of signal-dependent noise (SDN) on motor output. The
purpose of this study was to investigate the presence of SDN during
isometric force production and determine how central and peripheral
components contribute to this feature of motor control. Peripheral and
central components were distinguished experimentally by comparing
voluntary contractions to those elicited by electrical stimulation of
the extensor pollicis longus muscle. To determine other factors of motor-unit physiology that may contribute to SDN, a model was constructed and its output compared with the empirical data. SDN was
evident in voluntary isometric contractions as a linear scaling of
force variability (SD) with respect to the mean force level. However,
during electrically stimulated contractions to the same force levels,
the variability remained constant over the same range of mean forces.
When the subjects were asked to combine voluntary with
stimulation-induced contractions, the linear scaling relationship
between the SD and mean force returned. The modeling results highlight
that much of the basic physiological organization of the motor-unit
pool, such as range of twitch amplitudes and range of recruitment
thresholds, biases force output to exhibit linearly scaled SDN. This is
in contrast to the square root scaling of variability with mean force
present in any individual motor-unit of the pool. Orderly recruitment
by twitch amplitude was a necessary condition for producing linearly
scaled SDN. Surprisingly, the scaling of SDN was independent of the
variability of motoneuron firing and therefore by inference,
independent of presynaptic noise in the motor command. We conclude that
the linear scaling of SDN during voluntary isometric contractions is a
natural by-product of the organization of the motor-unit pool that does
not depend on signal-dependent noise in the motor command. Synaptic
noise in the motor command and common drive, which give rise to the variability and synchronization of motoneuron spiking, determine the
magnitude of the force variability at a given level of mean force output.
This article has been cited by other articles:
|
|
 |
|
  J. Izawa, T. Rane, O. Donchin, and R. Shadmehr Motor Adaptation as a Process of Reoptimization J. Neurosci., March 12, 2008; 28(11): 2883 - 2891. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Z. Z. Chew, S. C. Gandevia, and R. C. Fitzpatrick Postural control at the human wrist J. Physiol., March 1, 2008; 586(5): 1265 - 1275. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. E. Hudson, L. T. Maloney, and M. S. Landy Movement Planning With Probabilistic Target Information J Neurophysiol, November 1, 2007; 98(5): 3034 - 3046. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. G. Keenan and F. J. Valero-Cuevas Experimentally Valid Predictions of Muscle Force and EMG in Models of Motor-Unit Function Are Most Sensitive to Neural Properties J Neurophysiol, September 1, 2007; 98(3): 1581 - 1590. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. van Beers The Sources of Variability in Saccadic Eye Movements J. Neurosci., August 15, 2007; 27(33): 8757 - 8770. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. W. Franklin, G. Liaw, T. E. Milner, R. Osu, E. Burdet, and M. Kawato Endpoint Stiffness of the Arm Is Directionally Tuned to Instability in the Environment J. Neurosci., July 18, 2007; 27(29): 7705 - 7716. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. F. Medina and S. G. Lisberger Variation, Signal, and Noise in Cerebellar Sensory-Motor Processing for Smooth-Pursuit Eye Movements J. Neurosci., June 20, 2007; 27(25): 6832 - 6842. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. J. Schlicht and P. R. Schrater Impact of Coordinate Transformation Uncertainty on Human Sensorimotor Control J Neurophysiol, June 1, 2007; 97(6): 4203 - 4214. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Deneve, J.-R. Duhamel, and A. Pouget Optimal Sensorimotor Integration in Recurrent Cortical Networks: A Neural Implementation of Kalman Filters J. Neurosci., May 23, 2007; 27(21): 5744 - 5756. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. K. Barry, M. A. Pascoe, M. Jesunathadas, and R. M. Enoka Rate Coding Is Compressed But Variability Is Unaltered for Motor Units in a Hand Muscle of Old Adults J Neurophysiol, May 1, 2007; 97(5): 3206 - 3218. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. A. Christou, B. Poston, J. A. Enoka, and R. M. Enoka Different Neural Adjustments Improve Endpoint Accuracy With Practice in Young and Old Adults J Neurophysiol, May 1, 2007; 97(5): 3340 - 3350. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Scheidt and T. Stoeckmann Reach Adaptation and Final Position Control Amid Environmental Uncertainty After Stroke J Neurophysiol, April 1, 2007; 97(4): 2824 - 2836. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. C. Osborne, S. S. Hohl, W. Bialek, and S. G. Lisberger Time Course of Precision in Smooth-Pursuit Eye Movements of Monkeys J. Neurosci., March 14, 2007; 27(11): 2987 - 2998. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. M. Bays and D. M. Wolpert Computational principles of sensorimotor control that minimize uncertainty and variability J. Physiol., January 15, 2007; 578(2): 387 - 396. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Hirashima, K. Kudo, K. Watarai, and T. Ohtsuki Control of 3D Limb Dynamics in Unconstrained Overarm Throws of Different Speeds Performed by Skilled Baseball Players J Neurophysiol, January 1, 2007; 97(1): 680 - 691. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. P. J. Selen, J. H. van Dieen, and P. J. Beek Impedance Modulation and Feedback Corrections in Tracking Targets of Variable Size and Frequency J Neurophysiol, November 1, 2006; 96(5): 2750 - 2759. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Tanaka, J. W. Krakauer, and N. Qian An Optimization Principle for Determining Movement Duration J Neurophysiol, June 1, 2006; 95(6): 3875 - 3886. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. D. Takahashi, D. Nemet, C. M. Rose-Gottron, J. K. Larson, D. M. Cooper, and D. J. Reinkensmeyer Effect of muscle fatigue on internal model formation and retention during reaching with the arm J Appl Physiol, February 1, 2006; 100(2): 695 - 706. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Haruno and D. M. Wolpert Optimal Control of Redundant Muscles in Step-Tracking Wrist Movements J Neurophysiol, December 1, 2005; 94(6): 4244 - 4255. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. Mottram, E. A. Christou, F. G. Meyer, and R. M. Enoka Frequency Modulation of Motor Unit Discharge Has Task-Dependent Effects on Fluctuations in Motor Output J Neurophysiol, October 1, 2005; 94(4): 2878 - 2887. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. D. Sanger, J. Kaiser, and B. Placek Reaching Movements in Childhood Dystonia Contain Signal-Dependent Noise J Child Neurol, June 1, 2005; 20(6): 489 - 496. [Abstract] [PDF]
|
|
|
|
|
|
T. D. Sanger, J. Kaiser, and B. Placek Reaching Movements in Childhood Dystonia Contain Signal-Dependent Noise J Child Neurol, June 1, 2005; 20(6): 489 - 496. [Abstract] [PDF]
|
|
|
|
 |
|
 E. Todorov Stochastic Optimal Control and Estimation Methods Adapted to the Noise Characteristics of the Sensorimotor System Neural Comput., May 1, 2005; 17(5): 1084 - 1108. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Zhou and W. Z. Rymer Factors Governing the Form of the Relation Between Muscle Force and the EMG: A Simulation Study J Neurophysiol, November 1, 2004; 92(5): 2878 - 2886. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. W. Franklin, U. So, M. Kawato, and T. E. Milner Impedance Control Balances Stability With Metabolically Costly Muscle Activation J Neurophysiol, November 1, 2004; 92(5): 3097 - 3105. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Osu, N. Kamimura, H. Iwasaki, E. Nakano, C. M. Harris, Y. Wada, and M. Kawato Optimal Impedance Control for Task Achievement in the Presence of Signal-Dependent Noise J Neurophysiol, August 1, 2004; 92(2): 1199 - 1215. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. van Beers, P. Haggard, and D. M. Wolpert The Role of Execution Noise in Movement Variability J Neurophysiol, February 1, 2004; 91(2): 1050 - 1063. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Reinkensmeyer, M. G. Iobbi, L. E. Kahn, D. G. Kamper, and C. D. Takahashi Modeling Reaching Impairment After Stroke Using a Population Vector Model of Movement Control That Incorporates Neural Firing-Rate Variability Neural Comput., November 1, 2003; 15(11): 2619 - 2642. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. D. Takahashi, D. Nemet, C. M. Rose-Gottron, J. K. Larson, D. M. Cooper, and D. J. Reinkensmeyer Neuromotor Noise Limits Motor Performance, But Not Motor Adaptation, in Children J Neurophysiol, August 1, 2003; 90(2): 703 - 711. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. M. Taylor, E. A. Christou, and R. M. Enoka Multiple Features of Motor-Unit Activity Influence Force Fluctuations During Isometric Contractions J Neurophysiol, August 1, 2003; 90(2): 1350 - 1361. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
