![]() ![]() The small circle is the starting position, the double circle the goal position, the black arrow the planned displacement, and the gray arrow the actual (or observed) displacement. Schematic of adaptation to a force field perturbation (only the early phase of movement is described). the arm) toward the goal (the target) (2) a process, called goal selection ( GS orange), which provides the current goal for a given task. a target to reach) into the proper displacement of the current effector (e.g. The motor system contains: (1) a process, called action selection ( AS purple), which translates a current goal (e.g. when new patterns of force need to be learned.įig 1. ![]() Although the latter learning process appears more flexible and frugal than the former, it is unclear whether it can account for adaptation to dynamic perturbations, i.e. a remapping between target and movement vectors ( Fig 1C, right). For instance, adaptation to a visuomotor rotation of the visual display (kinematic perturbation) results from a redirection process, i.e. According to the second view, learning occurs at the goal selection level and modifies the mapping between intended and actual goals irrespective of how to achieve these goals ( Fig 1B, right). mapping is learned between goals and optimal forces to achieve the goals in the presence of the applied forces. mapping is learned between states and compensatory forces opposite to the applied forces ( Fig 1B, left and center see also Fig 1C, left and center for the case of a visuomotor rotation), or as a reoptimization process, i.e. For instance, in the typical laboratory example of adaptation to a velocity-dependent force field (dynamic perturbation ), learning has been described either as a compensation process, i.e. The first view holds that learning occurs at the action selection (control) level, and modifies the mapping between the intended goals and those actions inclined to achieve these goals ( Fig 1, purple). ![]() Motor learning and skill acquisition are generally understood from two distinct viewpoints. How then is skilled movement organized in response to these contrasting priorities? A proper balance between stability and flexibility is necessary so that (1) ingrained skills remain sensitive to steady and persistent changes in the environment, the body and the nervous system but are not disproportionately influenced by temporary, incidental events and (2) new skills can develop at any time. muscular fatigue, pain, …) can induce lasting changes in motor performance. wearing prismatic glasses, holding a visco-elastic manipulandum, …) or in some altered physiological state (e.g. On the other hand, a few movements performed in a novel sensorimotor environment (e.g. speech production, handwriting, gait, …) is maintained for decades, often robust in the face of injury, aging, disease or brain damage. On the one hand, a large repertoire of skilled, efficient behaviors (e.g. ![]() Their sleep isn't disturbed by the sounds outside their windows, because they have adapted to the noise.Motor behavior is both highly stable and widely flexible.
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