Humans make saccadic eye movements several times per second, on average, radically displacing the retinal image of objects from one view to the next. Why, then, is the world perceived as stable? In this study, the temporal integration of two brief motion pulses (150 ms) embedded in noise (10 s) was examined, both with maintained fixation and across eye movements. Motion coherence sensitivity was measured in a direction discrimination task as a function of the temporal delay between the two brief motion signals. When the subject made a 12 saccade from above to below the motion patch, temporal integration of motion continued across saccades, despite the fact that the retinotopic position of the stimulus changed as the result of a saccadic eye movement. This spatiotopic integration of motion occurred even when each brief motion stimulus was, by itself, below the threshold of conscious detection. Motion integration was not compulsory over the entire visual field, but depended on where the observer was looking and attending. These results suggest that the suppression of visual information during eye movements, combined with the integration of information about features of an attended object across eye movements, may be responsible for the perception of a stable world.
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