Marc Sommer, Ph.D.

Professor of Biomedical Engineering

Duke University

Faculty Host: Dr. Hey-Kyoung Lee

Neural mechanisms for visual continuity across eye movements

Abstract: Moving while sensing the world provides animals with quick, efficient behaviors but introduces big challenges for perception. The nervous system must distinguish sensory inputs caused by external agents from spurious inputs caused by one’s own actions. Primates face this problem every time they move their eyes, which in turn shifts the images across their retinas. Instead of perceiving the jostling of the retinal images, we perceive the world as continuous and stable, like a movie. We have learned a lot about neural circuits for visual continuity in primates. They involve feedback or “corollary discharge” from the brainstem to the frontal cortex. The process is not automatic, though, because all objects in the world are not the same. Creating a percept of continuity requires fore-knowledge or “priors” about whether objects are likely to move on their own or not. I will discuss recent computational, psychophysical, and neurophysiological studies that explore whether the use of priors by this system is Bayesian (spoiler alert: it is not).