Control of Eye Movements

Question 1

The cortical regions connect to the brainstem through the…

Answer 1

Internal capsule

Question 2

4 supranuclear eye movements

Answer 2

Saccadic
Pursuit
Vergence
Non-optic reflex

Question 3

7 supranuclear areas

Answer 3

Frontal gaze (voluntary) center
Occipital gaze (pursuit) center
Descending projections (internal capsule) to brainstem
Vergence center (midbrain)
Vertical gaze center (midbrain)
Horizontal gaze center (pons)
Medial longitudinal fasciculus

Question 4

Saccadic eye movements

Answer 4

Fast, voluntary eye movements
Controlled by the contralateral frontal cortex
Projects via internal capsule to brain stem gaze centers
Commonly affected (MCA stroke)

Question 5

Pursuit eye movements

Answer 5

Slow involuntary eye movements
Controlled by the occipital parietal cortex
Projects via internal capsule to brainstem

Question 6

Vergence eye movements

Answer 6

Slow, disconjugate eye movements
Controlled by occipital-parietal to midbrain pretectum
Allows for near focus

Question 7

Non-optic reflex

Answer 7

Slow eye movements
Controlled by vestibular nuclei in medulla, with inputs from labryinth and neck
Maintains fixtion during head movements

Question 8

3 oculomotor nuclei and where they are in the brainstem

Answer 8

III oculomotor complex (midbrain)
IV trochlear nucleus (midbrain)
VI abducens nucleus (pons)

Question 9

CN3 nerve nuclear complex controls…

Answer 9

Pupil (Edinger-Westphal nucleus), levator muscle

Inferior oblique, superior, medial and inferior rectus

Question 10

CN 4 nerve nucleus controls

Answer 10

Superior oblique muscle

Depresses and adducted eye

Question 11

CN 6 nerve nucleus controls

Answer 11

Lateral rectus muscle

Question 12

3 infranuclear structures

Answer 12

Cranial nerves 3, 4 and 6

Question 13

Frontal gaze palsy

Answer 13

Quite common
“Look towards the lesion” - lesion in frontal eye field
Can’t do voluntary movements to that side but can do pursuit and the non optic reflex

Question 14

What part of the brain controls the

1. Saccadic movements
2. Pursuit movements

Answer 14

1. Frontal eye fields

2. Occipital-parietal cortex

Question 15

Progressive supranuclear palsy

Answer 15

Gradual impairment f supranuclear gaze
Vertical > horizontal
Voluntary > pursuit > reflex
“Can’t look down syndrome” - eventually can’t move eyes at all
Associated with dementia - 5 to 8 year life expectance

Question 16

Midbrain Pre-tectal syndrom (Parinaud’s syndrome)

Answer 16

Dorsal midbrain syndrome
Vertical gaze palsy
Light near dissociated pupils (don't constrict to light)
Lid retraction/ptosis
Convergence-retraction nystagmus)
Very few other symptoms
From a tumor - quite treatable

Question 17

Internuclear opthlamoplegia (INO)

Answer 17

Lesion of the MLF
Going to affect the message to the medial rectus
Movement will be weak or slow
Other eye will have adducting nystagmus
Bilateral points to a demyelinating disease

Question 18

CN 3 nerve palsy

Answer 18

Most common is from an internal carotid artery aneurysm
Can get a pupil that doesn’t work
None of the muscles supplied by CN 3 work

Question 19

Cn 6 nerve palsy

Answer 19

Can’t move lateral rectus on the affected side
Saccades, pursuit and reflexes won’t work
Often from a hole from the lumbar puncture that causes pulling on the 6th nerve