Dr. Frederick A. Miles
Laboratory of Sensorimotor Research,
The National Eye Institute
will speak on
Vision and Eye Movements in a 3–D World
Abstract:
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
Hosted by the
Brain and Vision Research Laboratory