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Visuomotor adaptation and learning in human| old_uid | 11629 |
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| title | Visuomotor adaptation and learning in human |
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| start_date | 2012/09/13 |
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| schedule | 14h |
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| online | no |
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| summary | Theoretical and experimental attempts to distinguish between learning and adaptation
Adaptation and learning are often used interchangeably although they have been classically used to designate different physiological and behavioural phenomenon. We will consider theoretical reasons to distinguish between these two concepts and provide experimental arguments to support this view. Our behavioural data will suggest that learning and adaptation exhibit different spatial generalization properties and that transfer of adaptation between adaptation and learning is unidirectional.
Contributions of the cerebellum to acquisition and consolidation of motor memories : Polarity-sensitive effect of cerebellar stimulation
We also investigated the role of the cerebellum during acquisition of visuomotor learning. To investigate this question, we manipulated excitability of the cerebellum by applying anodal or cathodal transcranial direct current stimulation (tDCS) in a force field reaching. Anodal tDCS increased the rate of adaptation, while cathodal tDCS slowed it. Specifically, stimulation altered error-dependent learning : anodal tDCS increased sensitivity to error, whereas cathodal tDCS decreased it. This difference was particularly evident at movement onset, a time in which the movement mostly relies on planning. Early in training, the motor memory in all groups was fragile, exhibiting rapid decay in block of trials in which errors were artificially eliminated. With training, the motor memory became more stable only in the anodal and sham groups. Subjects returned on Day 2 and were re-tested on the task without stimulation. We observed that overnight, the motor memory had acquired further stability in the anodal group, but lost stability in the cathodal group. Furthermore, anodal stimulation during training produced a memory that attained additional stability in the post-training period. Therefore, the cerebellum plays a role in two fundamental motor memory processes : an error-dependent process that alters motor commands from trial to trial, and a trial- and/or time-dependent process that transforms the memory from fragile to stable. |
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| responsibles | Fenouil |
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