1. Society for Psychophysiological Research
Eye Movement Physiology Frank M. Marchak, Ph.D. Veridical Research and Design Corporation
Society for Psychophysiological Research
September

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

3. Why do you move your eyes?

4. Yarbus (1967)
Task influences eye movement behavior

5. Types of Eye Movements Gaze Stabilization Gaze shifting
Vestibulo-ocular
Optokinetic
Gaze shifting
Vergence
Smooth Pursuit
Saccade

6. Gaze Stabilization Vestibulo-Ocular Reflex
commons.wikimedia.org/wiki/File:Vestibulo-ocular_reflex_lateroflexion
_of_neck.svg
Stabilize eyes relative to external world
Compensate for head movements

7. Gaze Stabilization Optokinetic Nystagmus
img.springerimages.com/Images/ImagesMD/ATOPH/01/66/WATER_ATOPH B.jpg
Elicited by moving objects that produce illusion of head movement or slow head movements undetected by vestibular system
Visual-ocular response

8. Gaze Shifting Vergence
schorlab.berkeley.edu/vilis/vergence.htm
Align fovea of each eye with targets at different distances from observer
Disconjugate

9. Gaze Shifting Smooth Pursuit
Wetenbakerr,(1984). The Eye: Window on the World
Keep moving stimulus on fovea
Under voluntary control

10. Gaze Shifting Saccadic
Ballistic movements that abruptly change point of fixation

11. How do you move your eyes?

12. Extraocular Muscles
eyeaerobics.com/program/

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

14. Ophthalmotrope (Ruete, 1857)
The ophthalmotrope (Ruete, 1857; Helmholtz, 1867) was used mechanically to model eye movements with two artificial eyeballs that can turn around their centres on a ball pivot. The cords, which are fixed at extraocular eye muscle insertions, have weights tied to them to maintain the direction of action of the muscles. Whereas Ruete's model used anatomical variables only, Wundt's model also used physiological variables as muscle forces, represented by springs and weights. Remarkable in his analysis is that the spring constants of his model muscles were directly related to the cross-sectional area of the muscle and inversely related to the length of the muscle, as determined in post-mortem studies. As a matter of fact, Donders (1848) had already measured the weights of the muscles to determine their relative force. He found for human eye muscles that were dried at 100 deg C after removal of the tendon: 0.072, , , 0.075, and g for lateral, medial, superior and inferior rectus muscles, and superior and inferior oblique muscles, respectively.
bjo.bmj.com/content/93/5.cover-expansion

15. Extraocular Muscle Innervation

16. Extraocular Muscle Innervation Origins

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

18. Extraocular Muscle Innervation Ocular Motor Neuron Nuclei

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

20. 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

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

22. Neural Control of Saccades Pulse-Step
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

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

24. Neural Control of Saccades Horizontal Eye Movements
Purves, et al., (2004). Neuroscience
Excitatory pathways are shown in orange and the reciprocal inhibitory pathways are shown in blue. The particular pathway shown emanates from the frontal eye field (FEF), which projects through the anterior limb of the internal capsule, decussates to the opposite side at the midbrain-pontine junction, and then innervates the paramedian pontine reticular formation (PPRF). From there, projections directly innervate the lateral rectus (ipsilateral to the PPRF). A second decussation, back to the side of origin of FEF activation, via the MLF, innervates the medial rectus subnucleus of cranial nerve III and then neurons here project to innervate the medial rectus muscle. The right FEF command to trigger a saccade culminates in conjugate eye movements to the left. According to Herring's law, the horizontal yoke pair, the medial and lateral recti, are activated in synchrony.

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

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

27. 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

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

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

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

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

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

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

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

35. Neural Control of VOR
library.med.utah.edu/kw/animations/hyperbrain/oculo_reflex/oculocephalic2.html
lsda.jsc.nasa.gov/lsda_data/dil_data/msci1083.jpg

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