No abstract

We have studied the effect of rest breaks on sensorimotor adaptation to rotated visual feedback in a pointing task. Adaptive improvement was significantly poorer after 1-s breaks than after 5-40-s breaks, with no significant difference among the latter break durations. The benefit of >1-s breaks emerged soon after the onset of adaptation, and then remained steady throughout the adaptation, retention (next day), and persistence (no feedback) phases. This pattern of findings indicates that break-induced facilitation is not a result of strategic adjustments, motivation, or recovery from fatigue, but rather to consolidation of previously acquired sensorimotor recalibration rules.

Previous work has documented that the direction of eye and hand movements can be adaptively modified using the double-step paradigm. Here we report that both motor systems adapt not only to small direction steps (5° gaze angle) but also to large ones (28° gaze angle). However, the magnitude of adaptation did not increase with step size, and the relative magnitude of adaptation therefore decreased from 67% with small steps to 15% with large steps. This decreasing efficiency of adaptation may reflect the participation of directionally selective neural circuits in double-step adaptation.