Details

Autor(en) / Beteiligte

• Mackrous, Isabelle

Titel

Rôle de la vision pour le contrôle de la dynamique du mouvement lors d'un geste de pointage manuel chez l'adulte ainsi que chez l'enfant

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

2009

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• In previous research, the contribution of each source of sensory information for kinematic and dynamic processes has been studied independently. It is generally accepted that the visual afferent plays a dominant role for planning and control of kinematics, whereas the proprioceptive afferent is mostly linked to mechanisms underlying movement dynamics. However, it remains unclear how the central nervous system (CNS) integrates visual information in order to control said movement dynamics. A first hypothesis suggests that the two different sources of sensory information, vision and proprioception, are processed independently to sustain kinematic and dynamic control, respectively. A second hypothesis puts forward that mechanisms relying on vision interact with those that control movement dynamics. Indeed, the Specificity of practice hypothesis stipulates that visual information is processed at the expense of others sources of information for online control, possibly including online dynamic control. The goal of this thesis is to describe the role of visual and proprioceptive information in dynamic and kinematic online movement control. Our results show that: (1) Visual information is not processed at the expense of proprioceptive information. Most importantly, we have described a mechanism based on visual information which modulates the trajectory in the initial part of movement. (2) The complementary roles of visual and proprioceptive information, as well as their relative importance, are integrated in the neural representation of movement early on during childhood. We have also demonstrated that the development of an internal model of limb dynamic in children does not develop uniformly through the workspace. (3) Online modulation based on vision does not interfere with the development of a new internal dynamic model. Instead, its development interferes with the role of visual information which usually allows for modulations in the first portion of the trajectory. To summaries, our results support that the control of movement dynamics rely mostly on the processing of proprioceptive rather than visual information. On the other hand, we have demonstrated that visual information maintains its role for online modulation of movement (1) in the early part of movement trajectory (2) when dynamic is not perturbed (3) to sustain spatial accuracy. As we have established earlier, visual information's dominance for kinematic control is not absolute. Developing a new internal model of limb dynamic interferes with early visual control. Finally, the development of an internal model of limb dynamic in children is not uniformly distributed across the workspace; it begins close to one's midline and continues through eccentric workspace. Keys words: Visual information, proprioceptive information, internal model, dynamic, kinematics, online modulation, online correction, control, learning, children, video-aiming