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Article Dans Une Revue Neuroscience Année : 2016

On the nature of motor planning variables during arm pointing movement: Compositeness and speed dependence

Van Hoan Vu
  • Fonction : Auteur
Brice Isableu
  • Fonction : Auteur

Résumé

The purpose of this study was to investigate the nature of the variables and rules underlying the planning of unrestrained 3D arm reaching. To identify whether the brain uses kinematic, dynamic and energetic values in an isolated manner or combines them in a flexible way, we examined the effects of speed variations upon the chosen arm trajectories during free arm movements. Within the optimal control framework, we uncovered which (possibly composite) optimality criterion underlays at best the empirical data. Fifteen participants were asked to perform free-endpoint reaching movements from a specific arm configuration at slow, normal and fast speeds. Experimental results revealed that prominent features of observed motor behaviors were significantly speed-dependent, such as the chosen reach endpoint and the final arm posture. Nevertheless, participants exhibited different arm trajectories and various degrees of speed dependence of their reaching behavior. These inter-individual differences were addressed using a numerical inverse optimal control methodology. Simulation results revealed that a weighted combination of kinematic, energetic and dynamic cost functions was required to account for all the critical features of the participants' behavior. Furthermore, no evidence for the existence of a speed-dependent tuning of these weights was found, thereby suggesting subjectspecific but speed-invariant weightings of kinematic, energetic and dynamic variables during the motor planning process of free arm movements. This suggested that the inter-individual difference of arm trajectories and speed dependence was not only due to anthropometric singularities but also to critical differences in the composition of the subjective cost function.
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Origine : Publication financée par une institution

Dates et versions

hal-04262413 , version 1 (27-10-2023)

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Van Hoan Vu, Brice Isableu, Bastien Berret. On the nature of motor planning variables during arm pointing movement: Compositeness and speed dependence. Neuroscience, 2016, 328, pp.127-146. ⟨10.1016/j.neuroscience.2016.04.027⟩. ⟨hal-04262413⟩
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