Oculomotor Systems S. J. Potashner, Ph.D sjp9713@neuron.uchc.edu
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
Pupillary Control System Parasympathetic Stimulus: light Response: pupil constricts video Sympathetic Stimulus: an event or memory Response: pupil dilates, lids open wider video
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
Control of Horizontal Saccadic Eye Movements video
Control of Vertical Saccadic Eye Movements video
Upper Motor Neurons That Control Saccads Voluntary pathway Reflexive pathways
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
Control of Smooth Pursuit Eye Movements video
Control of Vergence Eye Movements Convergence Activation of both medial rectus muscles Lens curvature increased Pupil constricts Divergence ? video
Control of Vergence Eye Movements
Interaction of Vergence and Saccades during saccade saccade vergence after saccade vergence before saccade