2-2: Brain Sciences - 1/31: Oculomotor Control

Front 1

Conjugate VS Convergence Eye Movements

Back 1

Conjugate: eyes move in same direction (to right, to left)

Convergence: eyes converge in direction onto midline object

Front 2

Intorsion vs Extorsion

Back 2

Intorsion: move top of eye toward nose

Extorsion: move top of eye AWAY from nose

Front 3

Actions of superior oblique vs actions of inferior oblique

Back 3

Superior oblique: Depression, Abduction, Intorsion

Inferior oblique: Elevation, abduction, Extorsion

Front 4

How can you clinically test damage to CN IV?

Back 4

CN IV innervates superior oblique muscle

Have patient move eyes inward and down, see which eye is weaker

Front 5

What is head tild associated with? Why?

Back 5

CN IV palsy

Tilted head corrects diplopia (double vision) via rotating good eye (correction via vestibular system)

Front 6

What cranial nerves does the medial longitudinal fasciulus connect?

Back 6

CN III and CN VI

Front 7

Beginning with the lateral rectus of the left eye, outline the synapses that occur in order for the right eye to track horizontal motion.

Back 7

Lateral rectus synapses on Nucleus of CN VI

Nuc of CN VI crosses midline via Internuclear neurons of MLF

Internuclear neurons synapse on Nucleus of CN III

Synapses on Medial Rectus of right eye

Front 8

What are the symptoms of MLF Syndrome?

Back 8

MLF Syndrome = Internuclear Ophthalmoplegia

Symptoms:
1) Failure to ADDuct on side of lzn
2) Nystagmus in ABducting eye
3) convergence preserved (rules out CN III lezion)

Front 9

What is One and a Half Syndrome? Symptoms?

Back 9

interrupts CN VI in one eye and bilateral internuclear ophthalmoplegia

Symptoms:
1) No ABduction on side of lesion
2) No ADDuction on side of lzn and on opposite side too

Front 10

What are the non-ocular symptoms of MLF syndrome?

Back 10

Spasticity
Babinsky Sign
Aphasia
(Homonymous Hemianopia: loss of one side of visual field; same side in both sides)

Front 11

What is a saccade? When is it used?

Brain regions involved?

Back 11

Quick eye movement

Used during reading; eye jumps between points (moves image across retina)

Involves vestibular nucleus and cerebellum

Front 12

What is smooth pursuit? When is used?

Brian regions involved?

Back 12

Slow eye movement

Fixes an image on retina (fovea?); REQUIRES a visual target (ex: watch an airplane move across sky)

Sup colliculus, reticular formation of pons and midbrain

Front 13

What is the vestibulo-ocular reflex? Input required?

Back 13

Reflex that stabilized retinal image despite movements of the head

Doesn't require visual input, solely vestibular input

Front 14

What are optokinetic movements? Input requirements?

Back 14

Optokinetic movmts:
Slowly move eyes with target, then reset to next target (quick movmt = optokinetic nystagmus)

Requires visual input

Front 15

What kind of eye movement is the reticular formation important for?

Back 15

Vertical eye movements (sup/inf rectus, and obliques; CN III/IV with nuc in MIDBRAIN)

Front 16

What is Parinaud's Syndrome? Symptoms?

Back 16

Parinaud's = paralysis of upward gaze (can't look upward)

Symptom: spontaneous vertical nystagmus

Front 17

How could you clinically rule out a bilateral CN III lesion?

Back 17

Hold patient's eyelids up, ask to close eyelids

If eyes move upward, CN III intact

Front 18

Symptoms of a CN III palsy?

Back 18

Ptosis
Mydriasis (dilated pupil)

Front 19

What is the ocular effect of a cortical lesion?

Back 19

Tonic deviation of the eyes toward side of lesion