HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) supplemental data All Versions of this Article: 96/4/1991    most recent 00241.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (16) Citing Articles via Google Scholar Google Scholar Articles by Krouchev, N. Articles by Drew, T. Search for Related Content PubMed PubMed Citation Articles by Krouchev, N. Articles by Drew, T.

Sequential Activation of Muscle Synergies During Locomotion in the Intact Cat as Revealed by Cluster Analysis and Direct Decomposition

Département de Physiologie, Université de Montréal, Montreal, Quebec, Canada

Submitted 7 March 2006; accepted in final form 12 June 2006

During goal-directed locomotion, descending signals from supraspinal structures act through spinal interneuron pathways to effect modifications of muscle activity that are appropriate to the task requirements. Recent studies using decomposition methods suggest that this control might be facilitated by activating synergies organized at the level of the spinal cord. However, it is difficult to directly relate these mathematically defined synergies to the patterns of electromyographic activity observed in the original recordings. To address this issue, we have used a novel cluster analysis to make a detailed study of the organization of the synergistic patterns of muscle activity observed in the fore- and hindlimb during treadmill locomotion. The results show that the activity of a large number of forelimb muscles (26 bursts of activity from 18 muscles) can be grouped into 11 clusters on the basis of synchronous co-activation. Nine (9/11) of these clusters defined muscle activity during the swing phase of locomotion; these clusters were distributed in a sequential manner and were related to discrete behavioral events. A comparison with the synergies identified by linear decomposition methods showed some striking similarities between the synergies identified by the different methods. In the hindlimb, a simpler organization was observed, and a sequential activation of muscles similar to that observed in the forelimb during swing was less clear. We suggest that this organization of synergistic muscles provides a means by which descending signals could provide the detailed control of different muscle groups that is necessary for the flexible control of multi-articular movements.

This article has been cited by other articles:

				V. C. K. Cheung, A. d'Avella, and E. Bizzi Adjustments of Motor Pattern for Load Compensation Via Modulated Activations of Muscle Synergies During Natural Behaviors J Neurophysiol, March 1, 2009; 101(3): 1235 - 1257. [Abstract] [Full Text] [PDF]

				B. Berret, F. Bonnetblanc, C. Papaxanthis, and T. Pozzo Modular Control of Pointing beyond Arm's Length J. Neurosci., January 7, 2009; 29(1): 191 - 205. [Abstract] [Full Text] [PDF]

				T. M. Herter, T. Korbel, and S. H. Scott Comparison of Neural Responses in Primary Motor Cortex to Transient and Continuous Loads During Posture J Neurophysiol, January 1, 2009; 101(1): 150 - 163. [Abstract] [Full Text] [PDF]

				J. J. Kutch, A. D. Kuo, A. M. Bloch, and W. Z. Rymer Endpoint Force Fluctuations Reveal Flexible Rather Than Synergistic Patterns of Muscle Cooperation J Neurophysiol, November 1, 2008; 100(5): 2455 - 2471. [Abstract] [Full Text] [PDF]

				W. J. Kargo and S. F. Giszter Individual Premotor Drive Pulses, Not Time-Varying Synergies, Are the Units of Adjustment for Limb Trajectories Constructed in Spinal Cord J. Neurosci., March 5, 2008; 28(10): 2409 - 2425. [Abstract] [Full Text] [PDF]

				T. Drew, J. Kalaska, and N. Krouchev Muscle synergies during locomotion in the cat: a model for motor cortex control J. Physiol., March 1, 2008; 586(5): 1239 - 1245. [Abstract] [Full Text] [PDF]

				A. Frigon and S. Rossignol Short-Latency Crossed Inhibitory Responses in Extensor Muscles During Locomotion in the Cat J Neurophysiol, February 1, 2008; 99(2): 989 - 998. [Abstract] [Full Text] [PDF]

				Y. P. Ivanenko, G. Cappellini, N. Dominici, R. E. Poppele, and F. Lacquaniti Modular Control of Limb Movements during Human Locomotion J. Neurosci., October 10, 2007; 27(41): 11149 - 11161. [Abstract] [Full Text] [PDF]

				K. M. Friel, T. Drew, and J. H. Martin Differential Activity-Dependent Development of Corticospinal Control of Movement and Final Limb Position During Visually Guided Locomotion J Neurophysiol, May 1, 2007; 97(5): 3396 - 3406. [Abstract] [Full Text] [PDF]

				I. A. Rybak, N. A. Shevtsova, M. Lafreniere-Roula, and D. A. McCrea Modelling spinal circuitry involved in locomotor pattern generation: insights from deletions during fictive locomotion J. Physiol., December 1, 2006; 577(2): 617 - 639. [Abstract] [Full Text] [PDF]