Integration and segregation processes in motion perception

Official URL: https://risc01.sabanciuniv.edu/record=b3199884

The perception of motion requires the visual system to integrate inputs from various stages of motion processing. This thesis aims to contribute to our understanding of motion integration. Two studies were conducted for this purpose. The first study investigates how different motion perception systems integrate visual features. Our findings reveal that the position-based motion system, a motion perception system that relies on attentive tracking of object positions, binds moving features based on static cues like proximity and similarity. In contrast, the velocity-based motion system, which utilizes direction-selective cells, largely disregards these static cues. These results support previous findings that these motion systems can extract different motion information from the same stimulus. Furthermore, the discovery of distinct integration rules between these systems provides a novel contribution to the existing knowledge on motion integration. The second study addresses a limitation of the SSVEP methodology in motion perception research. It reveals that large-scale cortical dynamics can generate SSVEPs that mimic those produced by motion-sensitive neural populations by interacting with moving stimuli. We propose that randomizing the phase of position modulations across trials can overcome this issue by eliminating SSVEPs generated by large-scale cortical dynamics. These technical advancements have implications for past and future motion integration studies utilizing SSVEPs.