Heading Perception And Identification Of Scene-relative Object Motion From Optic Flow Information

The perception of the direction of self-motion(heading)and the identification of scenerelative object motion from optic flow(flow parsing)are basic functions for human survial.Previous studies have found that both of these two processes are based on the perception and anlysis of optic flow,and show similar performance in some visual tasks.However,there is still no conclusion about the neural mechanism of heading perception and flow parsing,and little is known about the temporal dynamics of these two processes.Here we addressed this question by examining how the accuracy of heading perception and flow parsing changes with exposure time to optic flow which simulated the forward self-motion.We found that flow parsing gains were below unity and decreased with exposure time to optic flow.At the same time,the accuracy of heading perception showed obvious central bias and increased with exposure time.We conclude that: first,solely visual information is not enough for accurate scene-relative object motion and heading perception.Besides,the opposite trend of temporal dynamics of heading perception and flow parsing suggests that although these two processes both rely on optic flow,they involve separate neural substrates and compete for the same limited attention resource.Furthermore,under object motion task,adaption effect was observed only in the full field optic flow condition,which means this process also depends on local motion information in the retinal vicinity of the moving object.