Eye Movements

Question 1

what are the two components to stabilize image on retina?

Answer 1

1. occulomotor system: eye in socket

head movement system: socket as whole with vestibular system

Question 2

Saccades does what to image?

Answer 2

shift fovea rapidly to new target

Question 3

what does smooth pursuit do?

Answer 3

keeps image of moving target on fovea

Question 4

what does optokinetic movements do?

Answer 4

holds image still during sustained head rotation

Question 5

6 extraocular muscles:

Answer 5

Superior Rectus
Inferior Rectus
Medial Rectus
Lateral Rectus

Inferior Oblique
superior Oblique

Question 6

Superior oblique movements?

Answer 6

torsion and depression adduction

Question 7

inferior oblique movements?

Answer 7

torsion and elevation

Question 8

Superior Oblique muscles innervated by?

Answer 8

trochlear: CNIV

Question 9

Lateral Rectus muscle innervated by?

Answer 9

Abducens: CN VI

Question 10

trochlear CN IV innervates which superior oblique?

Answer 10

the CONTRALATERAL one…

Question 11

what connects white matter tracts between cranial nerve nuclei?

Answer 11

medial longitudinal fasciculus (MLF)

Question 12

what reticular formation in the pons for coordinated eye movements?

Answer 12

pontine paramedian reticular formation

Question 13

what reticular formation in the midbrain for coordinated eye movements?

Answer 13

mesencephalic paramedian reticular formation

Question 14

What does Pontine RF coordinate? which nerves?

Answer 14

horizontal gaze

(MR)CN III and (LR)CNVI

Question 15

what does midbrain RF coordinate?

Answer 15

vertical gaze

(SO) CN IV and (SR)CN III

Question 16

two kinds of neurons fire during horizontal saccades?

Answer 16

burst neurons before movement

omnipause neurons fire when eye not moving

Question 17

Omnipause neurons do what?

Answer 17

inhibit via GABA

Question 18

Burst neurons do what kind of signalling?

Answer 18

excitatory for ipsilateral abducens

inhibitory for contralateral abducens

Question 19

what do you need for neural control of saccades?

Answer 19

simultaneous burst and inhibition of omnipause

Question 20

eye movements ultimately driven by?

Answer 20

behaviour

Question 21

what drives brainstem gaze centres? 5 things

Answer 21

frontal eye fields
post parietal cortex
superior colliculus
basal ganglia
cerebellum

Question 22

which nerves needed coordinates head and eye movements together?

Answer 22

vestibulocochlear to medulla nuclei with CNIII, CNVI nuclei