Relative Contributions of Motion and Position to Perception and Smooth Pursuit

Abstract:

There are at least two kinds of motion perception mechanisms. One computes motion using low-level

transient signal detectors and the other is a high-level system that compares an object’s position over

time. In my talk, I present two of my projects that explore the relative contributions of these two systems

to motion perception and smooth pursuit eye movements. In the first project, which was part of my PhD

thesis work, I combine evidence from a patient with parietal cortex damage, and normal observers to show

that high-level mechanisms are involved in processing slow motion, even when the motion is smooth and

continuous. In the second project, which is a recent study performed at Smith-Kettlewell, I use an illusory

motion stimulus and show that low-level motion integration is the dominant input to smooth pursuit eye

movements, especially for large objects that we often encounter in natural scenes. The combined results

provide insight into how signals from different motion processing systems are combined and used to

perceive and pursue moving objects by the human visual and oculomotor systems.