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Central and sensory contributions to the activation and organization of muscle synergies during natural motor behaviors.
- Source :
-
The Journal of neuroscience : the official journal of the Society for Neuroscience [J Neurosci] 2005 Jul 06; Vol. 25 (27), pp. 6419-34. - Publication Year :
- 2005
-
Abstract
- Previous studies have suggested that the motor system may simplify control by combining a small number of muscle synergies represented as activation profiles across a set of muscles. The role of sensory feedback in the activation and organization of synergies has remained an open question. Here, we assess to what extent the motor system relies on centrally organized synergies activated by spinal and/or supraspinal commands to generate motor outputs by analyzing electromyographic (EMG) signals collected from 13 hindlimb muscles of the bullfrog during swimming and jumping, before and after deafferentation. We first established that, for both behaviors, the intact and deafferented data sets possess low and similar dimensionalities. Subsequently, we used a novel reformulation of the non-negative matrix factorization algorithm to simultaneously search for synergies shared by, and synergies specific to, the intact and deafferented data sets. Most muscle synergies were identified as shared synergies, suggesting that EMGs of locomotor behaviors are generated primarily by centrally organized synergies. Both the amplitude and temporal patterns of the activation coefficients of most shared synergies, however, were altered by deafferentation, suggesting that sensory inflow modulates activation of those centrally organized synergies. For most synergies, effects of deafferentation on the activation coefficients were not consistent across frogs, indicating substantial interanimal variability of feedback actions. We speculate that sensory feedback might adapt recruitment of muscle synergies to behavioral constraints, and the few synergies specific to the intact or deafferented states might represent afferent-specific modules or feedback reorganization of spinal neuronal networks.
- Subjects :
- Afferent Pathways physiology
Animals
Electrodes, Implanted
Electromyography
Feedback
Hindlimb
Models, Neurological
Nerve Net physiology
Rhizotomy
Spinal Cord physiopathology
Spinal Nerve Roots surgery
Swimming physiology
Motor Activity physiology
Postural Balance physiology
Psychomotor Performance physiology
Rana catesbeiana physiology
Spinal Cord physiology
Spinal Nerve Roots physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1529-2401
- Volume :
- 25
- Issue :
- 27
- Database :
- MEDLINE
- Journal :
- The Journal of neuroscience : the official journal of the Society for Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 16000633
- Full Text :
- https://doi.org/10.1523/JNEUROSCI.4904-04.2005