Eye Movement Physiology Frank M. Marchak, Ph.D.

Veridical Research and Design Corporation www.vradc.com

Society for Psychophysiological Research September 14 2011

Eye Anatomy webvision.med.utah.edu/imageswv/Sagschem.jpeg

www.skybrary.aero/images/thumb/Vis_Fig2.jpg/500px-Vis_Fig2.jpg

Why do you move your eyes?

Yarbus (1967) Task influences eye movement behavior

Types of Eye Movements • Gaze Stabilization – Vestibulo-ocular – Optokinetic • Gaze shifting – Vergence – Smooth Pursuit – Saccade

Gaze Stabilization Vestibulo-Ocular Reflex commons.wikimedia.org/wiki/File:Vestibulo-ocular_reflex_lateroflexion _of_neck.svg

www.youtube.com/user/mbolding#p/u/15/PeO6w_bCz8U • Stabilize eyes relative to external world - Compensate for head movements

Gaze Stabilization Optokinetic Nystagmus www.youtube.com/watch?v=KSJksSA6Q-A&feature=related img.springerimages.com/Images/ImagesMD/ATOPH/01/66/WATER_ATOPH01-09 66-003B.jpg

• Elicited by moving objects that produce illusion of head movement or slow head movements undetected by vestibular system • Visual-ocular response

Gaze Shifting Vergence schorlab.berkeley.edu/vilis/vergence.htm

www.youtube.com/user/mbolding#p/u/16/9kgi_Avr66I • Align fovea of each eye with targets at different distances from observer - Disconjugate

Gaze Shifting Smooth Pursuit Wetenbakerr,(1984). The Eye: Window on the World • Keep moving stimulus on fovea - Under voluntary control www.youtube.com/watch?v=kEfz1fFjU78

Gaze Shifting Saccadic www.youtube.com/watch?v=FEJfAxJEP6E • Ballistic movements that abruptly change point of fixation

How do you move your eyes?

Extraocular Muscles eyeaerobics.com/program/

IO SR IO/SR SR/IO SR IO LR MR MR LR SO IR SO/IR IR/SO IR SO MR MR CONVERGENCE emedicine.medscape.com/article/1189759-overview

Ophthalmotrope (Ruete, 1857) bjo.bmj.com/content/93/5.cover-expansion

Extraocular Muscle Innervation

Extraocular Muscle Innervation Origins

Extraocular Muscle Innervation Ocular Motor Neuron Nuclei Purves, et al., (2004). Neuroscience

Extraocular Muscle Innervation Ocular Motor Neuron Nuclei

www.sharpsight.in/images/treatments/eye%20trackers.jpg

Saccadic Eye Movements express.howstuffworks.com/gif/body-saccidic-composite.jpg

Time Course of Saccades Purves, et al., (2004). Neuroscience • Two components • Amplitude • Lower motor neurons within oculomotor nuclei • Direction • Premotor neurons in gaze centers in brainstem

Neural Control of Saccades Purves, et al., (2004). Neuroscience Purves, et al., (2004). Neuroscience • Discharge frequency directly proportional to position and velocity of eye

Neural Control of Saccades Pulse-Step • Pulse - Tonic signal – eyes hold position - Height: speed of saccade - Duration: duration of saccade • Step - Phasic signal – eyes move - Height: amplitude of saccade brain.phgy.queensu.ca/pare/assets/Oculomotor%20lecture.pdf

Neural Control of Saccades Gaze Centers • Horizontal - Paramedian pontine reticular formation (PPRF) • Vertical - Rostral interstitial nucleus (rostral iMLF) cueflash.com/decks/CONTROL_OF_EYE_MOVEMENTS_-_57

Neural Control of Saccades Horizontal Eye Movements Purves, et al., (2004). Neuroscience

Horizontal Saccades Excitatory Burst Neurons • PPRF – Phasic signal of abducens motor neurons brain.phgy.queensu.ca/pare/assets/Oculomotor%20lecture.pdf

Horizontal Saccades Tonic Neurons • Nucleus prepositus hypoglossi – Tonic signal of abducens motor neurons brain.phgy.queensu.ca/pare/assets/Oculomotor%20lecture.pdf

Horizontal Saccades Inhibitory Burst Neurons • Paramedian pontine reticular formation (PPRF) – Inhibit contralateral abducens internuclear and motor neurons brain.phgy.queensu.ca/pare/assets/Oculomotor%20lecture.pdf

Horizontal Saccades Omnipause Neurons • Inhibit burst neurons in PPRF – Prevent saccades – Activate saccade burst generator brain.phgy.queensu.ca/pare/assets/Oculomotor%20lecture.pdf

Horizontal Saccades Superior Colliculus • Motor command - PPRF burst neurons • Trigger command - Omnipause neurons brain.phgy.queensu.ca/pare/assets/Oculomotor%20lecture.pdf

Superior Colliculus Topographic Motor Map Purves, et al., (2004). Neuroscience

Saccadic Eye Movements Higher Saccadic Centers cueflash.com/decks/CONTROL_OF_EYE_MOVEMENTS_-_57

Higher Saccadic Centers Frontal Eye Fields Purves, et al., (2004). Neuroscience

Higher Saccadic Centers Posterior Parietal Cortex camelot.mssm.edu/~ygyu/clip_image016_0001.jpg

Higher Saccadic Centers Basal Ganglia Purves, et al., (2004). Neuroscience

Neural Control of VOR lsda.jsc.nasa.gov/lsda_data/dil_data/msci1083.jpg

library.med.utah.edu/kw/animations/hyperbrain/oculo_reflex/oculocephalic2.html

Neural Control of Smooth Pursuit cueflash.com/decks/CONTROL_OF_EYE_MOVEMENTS_-_57