Virtual Reality in Motion Analysis to Characterize Disabilities in Limb Injury
This collaborative project with the Gait and Motion Laboratory, Providence VA Medical Center and Brown University,
will compare intraoperative reconstruction data for Anterior Cruciate Ligament tears with postoperative
function measured in the Gait Lab and in a virtual reality environment at Brown's Virtual Envrionment Navigation Laboratory (VENLab).
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The Sayles Swarm: How crowd behavior emerges from individual interactions
"To determine how crowd behavior emerges from individual actions, William Warren, professor of cognitive, linguistic,
and psychological sciences, assembled his own crowds and engaged them in an unusual four-day experiment in Sayles Hall.
The subjects were equipped with motion capture markers affixed like antennae to bike helmets."
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Optic Flow Drives Human Visuo-Locomotor Adaptation
Hugo Bruggeman, Wendy Zosh, William Warren.
Abstract Two strategies can guide walking to a stationary goal: (1) the optic-flow strategy,
in which one aligns the direction of locomotion or “heading” specified by optic flow with the visual goal 1 and 2;
and (2) the egocentric-direction strategy, in which one aligns the locomotor axis with the perceived egocentric
direction of the goal 3 and 4 and in which error results in optical target drift [5]. Optic flow appears to
dominate steering control in richly structured visual environments 2, 6, 7 and 8, whereas the egocentric-
direction strategy prevails in visually sparse environments 2, 3 and 9. Here we determine whether optic flow
also drives visuo-locomotor adaptation in visually structured environments. Participants adapted to walking
with the virtual-heading direction displaced 10° to the right of the actual walking direction and were then
tested with a normally aligned heading. Two environments, one visually structured and one visually sparse, were
crossed in adaptation and test phases. Adaptation of the walking path was more rapid and complete in the
structured environment; the negative aftereffect on path deviation was twice that in the sparse environment,
indicating that optic flow contributes over and above target drift alone. Optic flow thus plays a central
role in both online control of walking and adaptation of the visuo-locomotor mapping.
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