Vision and Eye Movements in a 3–D World

Frederick Miles

Laboratory of Sensorimotor Research,
The National Eye Institute

Primates have several reflexes that generate eye movements to compensate for bodily movements that would otherwise disturb their gaze and undermine their ability to process visual information. Two vestibulo–ocular reflexes utilize information from the labyrinths to compensate selectively for rotational and translational disturbances of the head, and several visuo–ocular reflexes curtail any residual disturbances of gaze by tracking the associated disturbances of the retinal images. This talk will concentrate on three independent visual tracking mechanisms that are selectively sensitive to different aspects of the visual disturbances associated with translation of the observer. They have ultra–short latencies and, though operating independently of perception, are probably cortically mediated. Two of these reflexes sense the observer’s motion by decoding the global pattern of optic flow, one sensing the flow experienced by the observer who looks in the direction of heading and the other the flow experienced by the observer who looks off to one side. The third reflex helps to maintain binocular alignment on the objects of interest by responding to any misalignments of their binocular images. Experiments designed to simulate some of the complications of real–world situations have uncovered levels of complexity that are surprising in such ultra–rapid reflex responses. I will argue that these eye movements provide new insights into the brain’s ability to parse the optic flow experienced by the observer who moves through a cluttered – and potentially confusing – visual world.

The lecture will take place:

in Room 203, 44 Cummington St.
on Friday, May 14th, 2004 at 3:00pm