Although pursuit eye movements are necessarily guided by visual feedback, the pursuit system also uses predictive control to improve performance. This is due to very large (about 100ms) delays in processing visual information about target location. In spite of these long delays, the eye can actually lead the target during sinusoidal pursuit at low frequencies. Predictive strategies also improve performance along more complicated trajectories. Our own work (Leung & Kettner 1997) & Kettner 1997) indicates that the eye lags the target by an average of only 3 ms for circles, 4 ms for sum-of-two-sines trajectories, and actually leads the target by 9 ms for sum-of-three-sines trajectories. In contrast, visual delays were estimated at 90 ms when the same monkeys responded to unpredictable perturbations. New experiments in progress indicate that half-circle, CW-to-CCW, and gap trajectories can be tracked using predictive control, but only after extended training. The proposed experiments will study single neuron responses in the flocculus and paraflocculus during the learning and/or performance of these new predictive behaviors. A biologically realistic model that shows how the flocculus/paraflocculus could generate predictive behaviors will also be tested. This work has clinical relevance. Deficits in oculomotor control are currently used as markers for clinical disorders such as schizophrenia and Parkinson's disease that involve deficits in thinking and motor processing. The measures of predictive control being developed in these studies will allow detailed assessments of predictive deficits. In addition, an understanding of how the brain learns predictive control may lead to strategies for rehabilitating patients.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY012984-05
Application #
6901856
Study Section
Visual Sciences B Study Section (VISB)
Program Officer
Hunter, Chyren
Project Start
2001-06-01
Project End
2008-05-31
Budget Start
2005-06-01
Budget End
2008-05-31
Support Year
5
Fiscal Year
2005
Total Cost
$220,500
Indirect Cost
Name
Northwestern University at Chicago
Department
Physiology
Type
Schools of Medicine
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
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Geruschat, Duane R; Hassan, Shirin E; Turano, Kathleen A et al. (2006) Gaze behavior of the visually impaired during street crossing. Optom Vis Sci 83:550-8
Kettner, R E; Suh, M; Davis, D et al. (2002) Complex predictive eye pursuit in monkey: a model system for cerebellar studies of skilled movement. Arch Ital Biol 140:331-40
Kettner, Ronald E; Suh, Minah; Davis, Dita et al. (2002) Modeling cerebellar flocculus and paraflocculus involvement in complex predictive smooth eye pursuit in monkeys. Ann N Y Acad Sci 978:455-67