Information pertaining to visual motion is used in the brain not only for conscious perception but also for various kinds of motorudcontrols. In contrast to the increasing amount of evidence supporting the dissociation of visual processing for action versus perception,udit is less clear whether the analysis of visual input is shared for characterizing various motor outputs, which require different kinds ofudinteractions with environments. Here we show that, in human visuomotor control, motion analysis for quick hand control is distinct fromudthat for quick eye control in terms of spatiotemporal analysis and spatial integration. The amplitudes of implicit and quick hand and eyeudresponses induced by visual motion stimuli differently varied with stimulus size and pattern smoothness (e.g., spatial frequency).udSurprisingly, the hand response did not decrease even when the visual motion with a coarse pattern was mostly occluded over the visualudcenter, whereas the eye response markedly decreased. Since these contrasts cannot be ascribed to any difference in motor dynamics, theyudclearly indicate different spatial integration of visual motion for the individual motor systems. Going against the overly unified hierarchicaludview of visual analysis, our data suggest that visual motion analyses are separately tailored from early levels to individual motorudmodalities. Namely, the hand and eyes see the external world differently.
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