Common synaptic input, synergies and size principle: control of spinal motor neurons for movement generation
Author(s)
Hug, Francois
Avrillon, Simon
Ibanez, Jaime
Farina, Dario
Type
Journal Article
Abstract
Understanding how movement is controlled by the CNS remains a major challenge, with ongoing debate about basic features underlying this control. In current established views, the concepts of motor neuron recruitment order, common synaptic input to motor neurons and muscle synergies are usually addressed separately and therefore seen as independent features of motor control. In this review, we analyse the body of literature in a broader perspective and we identify a unified approach to explain apparently divergent observations at different scales of motor control. Specifically, we propose a new conceptual framework of the neural control of movement, which merges the concept of common input to motor neurons and modular control, together with the constraints imposed by recruitment order. This framework is based on the following assumptions: (1) motor neurons are grouped into functional groups (clusters) based on the common inputs they receive; (2) clusters may significantly differ from the classical definition of motor neuron pools, such that they may span across muscles and/or involve only a portion of a muscle; (3) clusters represent functional modules used by the CNS to reduce the dimensionality of the control; and (4) selective volitional control of single motor neurons within a cluster receiving common inputs cannot be achieved. Here, we discuss this framework and its underlying theoretical and experimental evidence.
Date Issued
2023-01-01
Date Acceptance
2022-11-07
Citation
Journal of Physiology, 2023, 601 (1), pp.11-20
ISSN
0022-3751
Publisher
Wiley
Start Page
11
End Page
20
Journal / Book Title
Journal of Physiology
Volume
601
Issue
1
Copyright Statement
© 2022 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/36353890
Subjects
common drive
COMPARTMENTS
DRIVE
electromyography
HANDEDNESS
Life Sciences & Biomedicine
MOTONEURONS
motor modules
motor primitives
motor unit
MUSCLES
Neurosciences
Neurosciences & Neurology
ORGANIZATION
Physiology
PROJECTION
RECRUITMENT
Science & Technology
SHORT-TERM SYNCHRONIZATION
UNIT
Publication Status
Published
Coverage Spatial
England
Date Publish Online
2022-12-29