Auswirkungen visueller Umgebungsbedingungen auf motorisches Anpassungslernen. Forschungsdaten eines Experiments zur Sakkadenadaptation.
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Adaptation of saccade amplitude in response to intra-saccadic target displacement is a type of implicit motor learning which is required to compensate for physiological changes in saccade performance. Once established trials without intra-saccadic target displacement lead to de-adaptation or extinction, which has been attributed either to extra-retinal mechanisms of spatial constancy or to the influence of the stable visual surrounding. Therefore we investigated whether visual deprivation (“Ganzfeld”-stimulation or sleep) can partially maintain this motor learning compared to free viewing of the natural surroundings. Thirty-five healthy volunteers performed two adaptation blocks of 100 inward adaptation trials – interspersed by an extinction block – which were followed by a two hours break with or without visual deprivation (VD). Using additional adaptation and extinction blocks short- and long- (4 weeks) term memory of this implicit motor learning were tested. In the short term, motor memory tested immediately after free viewing was superior to adaptation performance after VD. In the long run, however, effects were opposite: motor memory and relearning of adaptation were superior in the VD conditions. This could imply independent mechanisms that underlie the short-term ability of retrieving learned saccadic gain and its long-term consolidation. We suggest that subjects mainly rely on visual cues (i.e. retinal error) in the free viewing condition which makes them prone to changes of the visual stimulus in the extinction block. This indicates the role of a stable visual array for resetting adapted saccade amplitudes. In contrast, visual deprivation (GS and sleep), might train subjects to rely on extra-retinal cues, e.g. efference copy or prediction to remap their internal representations of saccade targets, thus leading to better consolidation of saccadic adaptation.
Update Metadata: 2022-05-16 | Issue Number: 8 | Registration Date: 2015-03-12