Oxyopia Abstract

June 5, 2009
Friday, 5:00 PM
489 Minor Hall

Alex Huk, PhD
Assistant Professor, Section of Neurobiology, Dept. of Psychology, and Center for Perceptual Systems, University of Texas, Austin
Host: Michael Silver

Title

Neural basis of 3D motion perception

Abstract

Although much is known about how the primate visual system encodes both 2D motion and static depth, relatively little is known about how retinal motions and changing binocular disparities are used to perceive 3D motion. A fundamental question is whether the visual system encodes 3D direction by estimating changes in binocular disparity over time, or by computing interocular differences in patterns of retinal motion. In this talk I'll describe a series of human psychophysical and physiological experiments investigating the processing of these two primary binocular cues to 3D motion direction. A series of initial psychophysical experiments demonstrates that the visual system relies upon both differences in retinal velocities and changes in disparity over time, although these two cues exhibit vastly different speed tuning. A series of brain imaging experiments demonstrates that both of these cues are represented in human visual area MT+, but not in earlier cortical regions. A final set of psychophysical experiments suggests that the computation of interocular velocity differences operates upon eye-specific pattern motion signals. Taken together, these results demonstrate that the study of 3D motion is tractable, and stands to reveal novel signals in both well-understood and as-of-yet-unidentified brain circuits.

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