Muscle effort is best minimized by the right-dominant arm in the gravity field.
Fiche publication
Date publication
mars 2022
Journal
Journal of neurophysiology
Auteurs
Membres identifiés du Cancéropôle Est :
Pr MOUREY France, Pr PAPAXANTHIS Charalambos
Tous les auteurs :
Poirier G, Papaxanthis C, Mourey F, Lebigre M, Gaveau J
Lien Pubmed
Résumé
The central nervous system (CNS) develops motor strategies that minimize various hidden criteria, such as end-point variance or effort. A large body of literature suggests that the dominant arm is specialized for such open-loop optimization-like processes, whilst the non-dominant arm is specialized for closed-loop postural control. Building on recent results suggesting that the brain plans arm movements that take advantage of gravity effects to minimize muscle effort, the present study tests the hypothesized superiority of the dominant arm motor system for effort minimization. Thirty participants (22.5 ± 2.1 years old; all right-handed) performed vertical arm movements between two targets (40° amplitude), in two directions (upwards and downwards) with their two arms (dominant and non-dominant). We recorded the arm kinematics and electromyographic activities of the anterior and posterior deltoid to compare two motor signatures of the gravity-related optimization process; i.e., directional asymmetries and negative epochs on phasic muscular activity. We found that these motor signatures were still present during movements performed with the non-dominant arm, indicating that the effort-minimization process also occurs for the non-dominant motor system. However, these markers were reduced compared with movements performed with the dominant arm. This difference was especially prominent during downward movements, where the optimization of gravity effects occurs early in the movement. Assuming that the dominant arm is optimal to minimize muscle effort, as demonstrated by previous studies, the present results support the hypothesized superiority of the dominant arm motor system for effort-minimization.
Mots clés
Gravity, effort minimization, motor lateralization, motor planning, optimal control
Référence
J Neurophysiol. 2022 Mar 30;: