[Abstract Title]. - Society for Neuroscience

orientation was determined from spatial plots of the eye-in-head velocity data. To determine how
well the half-angle rule was obeyed, the tilt-angle coefficient was calculated as the angle of eye
velocity axis tilt divided by the angle of eye position eccentricity. During horizontal saccadic and
smooth pursuit eye movements, the half-angle rule was approximately obeyed, with tilt-angle
coefficients being close to 0.5. In contrast, the half-angle rule was not satisfied during vertical
saccadic and smooth pursuit eye movements, with tilt-angle coefficients being significantly less
than 0.5. We suggest that this discrepancy could arise due to differences in the degree of eye
position-dependent change in tendon pulling directions for the horizontal recti versus the vertical
recti and oblique muscles.
Disclosures: M.J. Thurtell, Department of Veterans Affairs, A. Employment (full or parttime);
A.C. Joshi, None; M.F. Walker, Department of Veterans Affairs, A. Employment (full or
part-time); R.J. Leigh, Department of Veterans Affairs, A. Employment (full or part-time); NIH
R01-EY06717, B. Research Grant (principal investigator, collaborator or consultant and pending
grants as well as grants already received); Evenor Armington Fund, B. Research Grant (principal
investigator, collaborator or consultant and pending grants as well as grants already received).
Poster
264. Eye Movements: Smooth Pursuit
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 264.17/DD34
Topic: D.06.d. Saccades and Pursuit
Support: CIHR
Canada Research Chair program
Title: Task dependent spatial updating of saccade targets during smooth pursuit
Authors: R. RADIK 1 , X. YAN 1 , *H. WANG 2 , J. F. X. DESOUZA 3 , J. CRAWFORD 1 ;
1 Dept. Biology, Ctr. of Vision Res., 2 Dept Psychol, 3 Dept. Psychology, York Univ., Toronto,
ON, Canada
Abstract: It is known that monkeys are able to spatially update the location of saccade targets
across an intermediate saccade or smooth pursuit (SP) movement (A. McKenzie and S. G.
Lisberger, J. Neurophysiology, 1986). Less is known about the dynamics of the underlying
neural signals during this updating, and how they might depend on instruction. In a recent
modeling study, we found that neural network models developed different types of spatial
remapping strategies depending on whether the metrics of an intervening SP movement were