L29 Eye Movements Flashcards Preview

Neuroscience > L29 Eye Movements > Flashcards

Flashcards in L29 Eye Movements Deck (28)
Loading flashcards...
1
Q

What are the 2 types of eye movements

A

conjugate eye movements (eyes moving together)

non-conjugate eye movements (eyes move in different directions)

2
Q

what movements fall under conjugate eye movements

A

saccadic movement/gaze
vestibulo-occular reflex
optokinetic reflex

3
Q

what is saccadic movement/gaze

A

voluntary movements

my eyes will “jump” from one point to the next point = scanning a picture

4
Q

what is the vestibule-occular reflex

A

uses vestibular system in the event that the head is spun/turned rapidly
keeps my eyes in position of former point of fixation

5
Q

what is the optokinetic reflex?

A

utilized in a situation such as watching landscape pass rapidly while I’m in a train
my eyes move rapidly to keep the object of focus in the center of the visual field for as long as possible

6
Q

what movements fall under non-conjugate movements?

A

vergence

dysconjugate gaze

7
Q

what is vergence?

A

convergence - eyes move towards each other

divergence - eyes move away from each other

8
Q

what is dysconjugate gaze?

A

pathological movement pattern -

eyes move erratically and totally independent of each other!

9
Q

what is the mneumonic for extraocular muscles and the nerves that innervate them

A

LR6(SO4)3

10
Q

where is the nerve nuclei for CN III and IV?

A

midbrain - tegmentum
CN III nuclei at level of SC
CN IV nuclei at level of IC

11
Q

what is the MLF?

A

for ascending neurons from abducens nucleus to occulomotor nucleus

12
Q

what is the role of superior colliculus? what eye movement can it participate in?

A

receives info from the retinal ganglion cells and can participate in saccadic eye movements

13
Q

what is MLF essential for

A

necessary for conjugate eye movement

14
Q

where is the nerve nuclei for CN VI located?

A

lower pons

15
Q

what is the role of PPRF

A

initial activate CN IV to begin conjugate eye movements (including saccadic eye movements)

16
Q

where is the vestibular nuclei located

A

from pons to the MEDULLA

17
Q

what does the vestibular nuclei control

A

the vestibulo-ocular reflex

18
Q

what is the role of the cerebellum (particularly the vestibule-cerebellum) ?

A

participates in the optokinetic reflex

19
Q

what is the role of the frontal eye field ?

A

role in planning and initiation of eye movements (seen in saccadic eye movements)

20
Q

what brodmanns area corresponds to the frontal eye field?

A

Area 8

21
Q

what is the location and role of the parieto-occipital eye field?

A

at junctions of parietal and occipital lobe

output is involved in depth and motion

22
Q

what is the purpose of saccadic eye movements

A

extremely fast movements used to keep the target in focus on the fovea (used for scanning)

23
Q

how will a trochlear nerve palsy (CN IV) present?

A

eye = up and in

unopposed IO

24
Q

how will a occulomotor nerve palsy (CN III) present?

A

eye = down and out

unopposed LR and SO

25
Q

how will a abducens nerve palsy (CN VI) present?

A

eye = medial deviation

unopposed MR

26
Q

describe diplopia

A

causes by the fact that an image is landing on different points of the visual field for each eye because one eye is unable to focus the image properly on the fovea

when V1 gets the info - it registers it as actually existing in 2 places = double vision

27
Q

what is an internuclear ophthalmoplegia

A

lesion of MLF
abducens n. cannot transmit info to oculomotor n.
so same side MR cannot work

28
Q

what is a PPRF lesion?

A

= inability to trigger same abducens n. = inability to initiate and send info up the MLF

Decks in Neuroscience Class (54):