MOTION INTEGRATION OVER SPACE - INTERACTION OF THE CENTER AND SURROUND MOTION

Motion integration occurs over a restricted range of visual space, How ever, there have been studies suggesting interactions among motion det ectors operating on widely separated spatial regions. To understand th ese lateral spatial interactions beyond motion pooling regions, we exa mined the effect of surrounding motion on the direction of the center stimulus under several stimulus conditions. We have found that there i s a motion direction shift of the center stimulus caused by surroundin g motion depending on its motion direction, spatial proximity to the c enter stimulus, contrast, speed, and the extent of motion area. This e ffect was observed both for monocular and dichoptic presentations of t he pattern. However, the perceived direction shift decreased when the spatial frequency ratio of the center and surround stimuli varied, or a non-Fourier motion pattern was used for both center and surround sti muli. We present a model consisting of lateral inhibitory interactions between pattern motion unit networks to explain the direction shift o bserved in the experiments. (C) 1997 Elsevier Science Ltd.