temporal integration of movement the time-course of motion streaks revealed by masking时间集成运动运动条纹显示的时间进程屏蔽.pdf

Temporal Integration of Movement: The Time-Course of Motion Streaks Revealed by Masking 1 1 2 3 David Alais , Deborah Apthorp *, Anna Karmann , John Cass ¨ 1 School of Psychology, University of Sydney, Sydney, New South Wales, Australia, 2 Universitat Regensburg, Regensburg, Germany, 3 School of Psychology, University of Western Sydney, Sydney, New South Wales, Australia Abstract Temporal integration in the visual system causes fast-moving objects to leave oriented ‘motion streaks’ in their wake, which could be used to facilitate motion direction perception. Temporal integration is thought to occur over *100 ms in early cortex, although this has never been tested for motion streaks. Here we compare the ability of fast-moving (‘streaky’) and slow-moving fields of dots to mask briefly flashed gratings either parallel or orthogonal to the motion trajectory. Gratings were presented at various asynchronies relative to motion onset (from {200 to z700 ms) to sample the time-course of the accumulating streaks. Predictions were that masking would be strongest for the fast parallel condition, and would be weak at early asynchronies and strengthen over time as integration rendered the translating dots more streaky and grating-like. The asynchrony where the masking function reached a plateau would correspond to the temporal integration period. As expected, fast-moving dots caused greater masking of parallel gratings than orthogonal gratings, and slow motion produced only modest masking of either grating orientation. Masking strength in the fast, parallel condition increased with time and reached a plateau after 77 ms, providing an estimate of the temporal integration period fo