Title
The human sensorimotor cortex fosters muscle synergies through cortico-synergy coherence.
Abstract
In neuromotor control, the dimensionality of complex muscular activation patterns is effectively reduced through the emergence of muscle synergies. Muscle synergies are tailored to task-specific biomechanical needs. Traditionally, they are considered as low-dimensional neural output of the spinal cord and as such their coherent cortico-muscular pathways have remained underexplored in humans. We investigated whether muscle synergies have a higher-order origin, especially, whether they are manifest in the cortical motor network. We focused on cortical muscle synergy representations involved in balance control and examined changes in cortico-synergy coherence accompanying short-term balance training. We acquired electromyography and electro-encephalography and reconstructed cortical source activity using adaptive spatial filters. The latter were based on three muscle synergies decomposed from the activity of nine unilateral leg muscles using non-negative matrix factorization. The corresponding cortico-synergy coherence displayed phase-locked activity at the Piper rhythm, i.e., cortico-spinal synchronization around 40 Hz. Our study revealed the presence of muscle synergies in the motor cortex, in particular, in the paracentral lobule, known for the representation of lower extremities. We conclude that neural oscillations synchronize between the motor cortex and spinal motor neuron pools signifying muscle synergies. The corresponding cortico-synergy coherence around the Piper rhythm decreases with training-induced balance improvement.
Year
DOI
Venue
2019
10.1016/j.neuroimage.2019.05.041
NeuroImage
Keywords
Field
DocType
Motor control,Muscle synergies,Cortico-muscular connectivity,Electro-encephalography,Electromyography,Postural stability
Spinal cord,Motor neuron,Neuroscience,Electromyography,Psychology,Cognitive psychology,Motor control,Coherence (physics),Motor cortex,Rhythm,Paracentral lobule
Journal
Volume
ISSN
Citations 
199
1053-8119
0
PageRank 
References 
Authors
0.34
0
4
Name
Order
Citations
PageRank
Coen S Zandvoort100.34
Jaap H. van Dieën2243.85
Nadia Dominici300.34
a daffertshofer49712.77