Muscular synergies underlying complex upper-limb movements: from fundamental research to clinical application.

Daily-life movements are complex in the sense that they have a goal, they imply the rotation of many joints with multiple degrees of freedom and they require the coordinated activation of numerous muscles. How the central nervous system (CNS) accomplishes the planning and the execution of these behavioral movements is a central subject of study from both fundamental and clinical point of views. Since a number of years now an increasing number of scientific works are bringing insights about the basis of muscular synergies and the temporal aspects of the muscular command. And new theories of motor control about cyclic movements versus discrete movements, for upper limb, are challenging the way to think about movement rehabilitation.
Studies relating to the sequencing of movements and their temporal organization (from kinematic parameters to muscular activity) performed with persons suffering from pathologies concerning the central nervous system may help us to understand the different mechanisms underlying the control of complex movements. Indeed studying movement disorders from a broad category of pathologies, going from sensori-motor syndromes to cognitive problems, may also help to understand the function of neural structures in the planning and execution of the muscular command. In this research topic we would like to address the following questions: What parameters of movement control and underlying the muscular synergies are managed by the spinal and/or the central neural networks? In other words which aspects of muscular commands and muscular synergies organization are central and which are spinal for complex upper limb movements? What is the influence of sensory and cognitive information for the modulation of muscular synergies? In the cases of an altered neuro-biomechanical, musculo-squelettal system, for example a limb with spasticity, what are the consequences for the planning and execution of the muscular command? Are the same solutions implemented by children with cerebral palsy and by adults with stroke? Taking into consideration the cognitive and sensori-motor dimensions of complex upper limb movements will lead to improved reeducation programs for each type of pathology.
The present Research Topic in Frontiers in Neurology is dedicated to understanding muscular commands underlying complex upper limb movements in healthy and pathological situations. We welcome original research, methodological, theoretical, review, and perspective contributions from scientists and clinicians.