Abstract
Predictions of three models of single-joint motor control were compared with experimental observations of the changes in electromyographic (EMG) patterns during fast voluntary movements against an unexpectedly reduced inertial load. The subjects performed elbow flexions over 40° “as fast as possible” in two series. During the first series, an approximately 40% decrease in inertia, simulated by a torque-motor, might occur unpredictably on half of the trials (unloaded trials). During the second series, all the trials were unloaded. The major findings are: (1) no differences in the antagonist burst latency in unexpectedly unloaded and unperturbed trials; (2) a decrease in the antagonist latency during expected unloadings; (3) a small, statistically non significant decrease in the first agonist burst EMG integral; and (4) a larger, statistically significant increase in the antagonist burst EMG integral in unexpectedly unloaded trials as compared to unperturbed trials. The data are in good correspondence with a version of the equilibrium-point hypothesis that assumes central programming of the beginning of the antagonist burst and incorporates the possibility of reflex-induced changes in EMG amplitudes.
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References
Abdusamatov RM, Feldman AG (1986) Description of the electromyograms with the aid of a mathematical model for single joint movements. Biophysics 31:549–552
Brown SH, Cooke JD (1981) Responses to force perturbations preceding voluntary human arm movements. Brain Res 220:350–355
Corcos DM, Gottlieb GL, Agarwal GC (1989) Organizing prinicples for single joint movements. II. A speed-sensitive strategy. J Neurophysiol 62:358–368
Corcos DM, Gottlieb GL, Agarwal GC, Flaherty BP (1990) Orga nizing prinicples for single joint movements. IV. Implications for isometric contractions. J Neurophysiol 64:1033–1042
Denier van der Gon JJ, Wadman WJ (1977) Control of fast balli stic human arm movements. J Physiol (Lond) 271:28–29P
Feldman AG (1966) Functional tuning of the nervous system with control of movement or maintenance of a steady posture. II. Controllable parameters of the muscle. Biophysics 11:565–578
Feldman AG (1986) Once more on the equilibrium-point hypothesis (1 model) for motor control. J Mot Behav 18:17–54
Feldman AG, Adamovitch SV, Ostry DJ, Flanagan JR (1990) The origin of electromyograms — explanations based on the equili brium point hypothesis. In: Winters JM, Woo SL-Y (eds) Mul tiple muscle systems. Biomechanics and movement organiza tion. Springer, Berlin Heidelberg New York, pp 195–213
Gottlieb GL, Corcos DM, Agarwal GC (1989a) Strategies for the control of voluntary movements with one mechanical degree of freedom. Behav Brain Sci 12:189–250
Gottlieb GL, Corcos DM, Agarwal GC (1989b) Organizing principles for single joint movements. I. A speed-insensitive strategy. J Neurophysiol 62:342–357
Gottlieb GL, Corcos DM, Agarwal GC, Latash ML (1990) Orga nizing principles for single joint movements. III. Speed insen sitive strategy as a default. J Neurophysiol 63:625–636
Gottlieb GL, Latash ML, Corcos DM, Liubinskas TJ, Agarwal GC (1992) Organizing prinicples for single joint movements. V. Agonist antagonist interactions. J Neurophysiol 67:1417–1427
Latash ML, Gottlieb GL (1991a) An equilibrium-point model of dynamic regulation for fast single joint movements. I. Emer gence of strategy dependent EMG patterns. J Mot Behav 23:163–177
Latash ML, Gottlieb GL (1991b) An equilibrium-point model of dynamic regulation for fast single-joint movements. II. Simila rity of isometric and isotonic programs. J Mot Behav 23:179–191
Latash ML, Gottlieb GL (1991c) Reconstruction of joint com pliant characteristics during fast and slow movements. Neuroscience43:697–712
Latash ML, Gottlieb GL (1992) Virtual trajectories of single joint movements performed under two basic strategies. Neuroscience 47:357–365
Lee RG, Lucier GE, Mustard BE, White DG (1986) Modification of motor output to compensate for unanticipated load conditions during rapid voluntary movements. Can J Neurol Sci 13:97–102
Lestienne F (1979) Effects of inertial loads and velocity on the braking process of voluntary limb movements. Exp Brain Res 35:407–418
Mustard BE, Lee RG (1987) Relationship between EMG patterns and kinematic properties for flexion movements at the human wrist. Exp Brain Res 66:247–256
Sanes JN, Jennings VA (1984) Centrally programmed patterns of muscle activity in voluntary motor behavior of humans. Exp Brain Res 54:23–32
Sherwood DE, Schmidt RA, Walter CB (1988) Rapid movements with reversals in direction. II. Control of movement amplitude and inertial load. Exp Brain Res 69:355–367
Smeets JBJ, Erkelens CJ, Denier van der Gon JJ (1990) Adjust ments of fast goal directed movements in response to an unexpected inertial load. Exp Brain Res 81:303–312
Stein RB, Cody FWJ, Capaday C (1988) The trajectory of human wrist movements. J Neurophysiol 59:1814–1830
Wadman WJ, Denier van der Gon JJ, Geuze RH, Mol CR (1979) Control of fast goal directed arm movements. J Hum Mov Studies 5:3–17
Wallace SA (1981) An impulse timing theory for reciprocal control of muscular activity in rapid, discrete movements. J Mot Behav 13:144–160
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Latash, M.L. Control of fast elbow movement: a study of electromyographic patterns during movements against unexpectedly decreased inertial load. Exp Brain Res 98, 145–152 (1994). https://doi.org/10.1007/BF00229119
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DOI: https://doi.org/10.1007/BF00229119