Lecture 9, Eye movements

Question 1

Intorsion

Answer 1

movement of upper pole of the eye inward

Question 2

Extorsion

Answer 2

movement of upper pole of eye outward

Question 3

Oculomotor nuclei

Answer 3

located in the rostral midbrain at the level of the superior colliculi and red nucleus, ventral to PAG

Question 4

Edinger-Westphal nuclei

Answer 4

contain preganglionic parasympahetic fibers

Question 5

Trochlear nerve

Answer 5

located in caudal midbrain at level of inferior colliculi and decussation of superior cerebellar peduncle

exit at the level of anterior medullary velum

Question 6

Trochlear nerves are the ______ CNs to exit the brain _____

Answer 6

ONLY
dorsally

Question 7

Abducens nuclei

Answer 7

lie on floor of fourth ventricle
exits at pontomedullary junction, travels to subrarachnoid space, enters dorello’s canal

Question 8

Roof of 4th ventrile

Answer 8

anterior medullary velum

Question 9

Pupillary Constriction, Parasympathetic Pathway

Answer 9

light activates retinal ganglion cells, projects to both optic tracts, superior colliculus, pretectal nucleus, EWN, travels via CN 3, ciliary ganglia , pupillary constrictor muscles

Question 10

Simplified version of pupillary constriction

Answer 10

light shown in one eye causes direct response pathway from contralateral EDW causes same response in oppoiste eye called consensual response

Question 11

Convergence

Answer 11

bringing gaze toward midline, tracking object coming close to nose
caused by medial recti

Question 12

Divergence

Answer 12

bringing gaze further from midline, tracking object moving away from nose
caused by lateral recti

Question 13

Saccades

Answer 13

rapid eye movments
bring targets of interest into field of view
vision is suppressed during saccade
can be voluntary or reflexive

Question 14

Smooth pursuit

Answer 14

eye movements not under voluntary control
allow for stable viewing/tracking of moving obkects

Question 15

Vergence

Answer 15

eye movements to maintain fused fization by both eyes as tragets move toward or away from the viewer

Question 16

Nystagmus

Answer 16

rhythmic form of reflex eye movements
compoased of slow movements in one direction, interrupted by fast, saccade-like movements in the opposite direction

Question 17

MLF

Answer 17

interconnects the oculomotor, trochlear, abducens and vestibular nuclei
eye movements are yoked together

Question 18

Pathways for Horizontal Gaze

Answer 18

Frontal Eye Fields to PPRF to Abducens nuclei to CN VI root to lateral rectus

PPRF to Abducens nuclei to MLF to CN III to medial rectus

Question 19

Frontal eye fields

Answer 19

saccades

Question 20

Contralateral eye movements

Answer 20

smooth pursuits