1. Oculomotor Systems
S. J. Potashner, Ph.D

2. Eye Motor Systems Control tears & blinking – protects the eye surface
Control pupils – light compensation; sympathetic response
Control gaze & lens curvature – moves eyes onto a target
Saccades
Smooth pursuit
Vergence
Control gaze during head movement – stabilize eyes on target

3. Pupillary Control System
Parasympathetic
Stimulus: light
Response: pupil constricts
video
Sympathetic
Stimulus: an event or memory
Response: pupil dilates,
lids open wider
video

4. Eye Movements Fixation holds foveas still
Saccade shifts both foveas to an alternate target
Smooth pursuit keeps both foveas on a moving target
Vergence keeps both foveas on an approaching or receding target
Optokinetic keeps both foveas on target during head movement

5. Control of Horizontal Saccadic Eye Movements
video

7. Control of Vertical Saccadic Eye Movements
video

8. Upper Motor Neurons That Control Saccads
Voluntary
pathway
Reflexive
pathways

9. Eye Movements Fixation holds foveas still
Saccade shifts both foveas to an alternate target
Smooth pursuit keeps both foveas on a moving target
Vergence keeps both foveas on an approaching or receding target
Optokinetic keeps both foveas on target during head movement

10. Control of Smooth Pursuit Eye Movements
video

11. Control of Vergence Eye Movements
Convergence
Activation of both
medial rectus muscles
Lens curvature increased
Pupil constricts
Divergence ?
video

12. Control of Vergence Eye Movements

13. Interaction of Vergence and Saccades
during saccade
saccade
vergence
after saccade
vergence
before saccade