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Abstract

2. Acknowledgments: The authors wish to thank Diana Meyers for her valuable assistance in the preparation of the manuscript and figures.-1 A neural model is developed of how motion integration and segmentation processes, both within and across apertures, compute global motion percepts. Figure-ground properties, such as occlu-sion, influence which motion signals determine the percept. For visible apertures, a line’s termina-tors do not specify true line motion. For invisible apertures, a line’s intrinsic terminators create veridical feature tracking signals. Sparse feature tracking signals can be amplified before they propagate across position and are integrated with ambiguous motion signals within line interiors. This integration process determines the global percept. It is the result of several processing stages: Directional transient cells respond to image transients and input to a directional short-range filter that selectively boosts feature tracking signals with the help of competitive signals. Then a long-range filter inputs to directional cells that pool signals over multiple orientations, opposite con-trast polarities, and depths. This all happens no later than cortical area MT. The directional cell