The feedforward control of posture and movement
Notice bibliographique
Résumé
Goal-directed arm movements performed in the standing position potentially disturb the body's equilibrium as a result of the multi-linked structure of the musculoskeletal system. To compensate for these disturbances and ensure that stability is maintained, the central nervous system (CNS) organizes postural adjustments preceding and accompanying the voluntary movement in a feedforward manner (Massion 1992) using knowledge of the dynamics of the body (Bouisset and Zattara 1981). To date, most studies investigating the control of posture during voluntary movements in humans have focused on either the role of the postural activity preceding the movement or on the temporal structure of these anticipatory postural adjustments (APAs) with respect to the focal movement. As such, detailed knowledge about the spatial organization of postural activity is lacking. Furthermore, it is not clear how posture is coordinated when the goal of a voluntary movement changes online. Therefore, the studies in this thesis were aimed at addressing these questions to develop a greater understanding of the organization of feedforward postural control during voluntary movements. Muscle activity, kinetics and kinematics were recorded as subjects performed unperturbed and perturbed reaching movements to targets located in multiple directions while standing. Feedforward postural control strategies preceding and accompanying the reaching movements were quantified. Characterization of the spatial and temporal patterns of muscle activity and ground reaction forces of postural adjustments preceding reach movements revealed that muscle activity was directionally-tuned to reach direction and forces that were constrained to two principal directions. Also, muscle synergies were able to explain the spatial and temporal variability in postural muscle activity in the period preceding the reaching movements, suggesting that a modular organization of muscle recruitment is adopted for this task. Overall, these strategies are similar to those observed for feedback postural responses, suggesting that the CNS relies on shared neural structures for controlling posture in both modes of control. Lastly, the nature of postural control was examined when reaching movements were perturbed with a shift of the visual target after the reaching movement was initiated. Here, muscle activity in the legs was consistently modulated prior to changes in the muscle activity related to the online correction of the arm trajectory.Taken together, the findings of this thesis provide important insights into how the brain coordinates the control of posture and movement. This work provides a measure of feedforward postural control strategies in healthy, young adults as a first step to understanding how and why deficits in balance control may occur during the execution of voluntary movements in fall-prone individuals.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».