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aNeuro Exam 3- Lindsey's > Eye Movements > Flashcards

Eye Movements Flashcards

1
Q

What is the representation of the optic disk in the visual field?

A

the blind spot

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2
Q

This is moving the fovea to an object closer (convergence) or farther away (divergence).

A

vergence

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3
Q

What signals the rotation of the head?

A

the semicircular canals

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4
Q

Saccades can be voluntarily generated by the _____.

A

frontal eye field (FEF)

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5
Q

The oculomotor system is subject to modulation by the ____ and ____.

A

cerebellum; basal ganglia

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6
Q

What is inhibited during conjugate gaze?

A

antagonist motor neurons

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7
Q

When is nystagmus normal?

A

when the head is rotated for along time or when there is a moving visual stimulus

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8
Q

What initiate conjugate eye movements?

A

a variety of sensory inputs, especial visual and vestibular

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9
Q

What are the 2 important control centers for saccades?

A
  1. the cortex
  2. the superior colliculus
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10
Q

If the head turns to the right, the eyes ____.

A

counter rotate to the L

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11
Q

Smooth pursuit can only maintain foveation at a rate of about _____.

A

50 degrees/second

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12
Q

The direction of the nystagmus is defined by _____.

A

the direction of the rapid saccade

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13
Q

What are saccades?

A

rapid, ballistic eye movements (to bring an object onto the fovea)

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14
Q

Where is the pattern generator for horizontal saccades?

A

in the reticular formation near the abducens nucleus (the paramedian pontine reticular formation- PPRF)

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15
Q

What eye condition do MS patients often get?

A

internuclear ophthalmoplegia (INO)

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16
Q

Cells in the vestibular nuclei project by way of the ______ to excite lateral rectus motor neurons in the abducens nucleus.

A

medial longitudinal fasciculus (MLF)

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17
Q

Saccades can be reflexively directed from the _____.

A

parietal eye field (PEF)

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18
Q

If the frontal eye field is damaged, the is a _____.

A

temporary loss of the ability to generate saccades

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19
Q

Interruption of the _____ can cause discoordination of medial and lateral recti muscles during horizontal gaze movements, called internuclear ophthalmoplegia (INO).

A

medial longitudinal fasciculus (MLF)

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20
Q

Coordinate contraction of the 2 eyes is accomplished by _____ that reside in the vicinity of the oculomotor and abducens nuclei.

A

interneuronal pattern generators

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21
Q

What is an example of a vergence movement?

A

when both eyes turn towards the nose for near reading

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22
Q

Horizontal saccades are driven ____.

A

contralaterally

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23
Q

What are the vestibular ocular reflex (VOR) and optokinetic nystagmus (OKN) eye movements?

A

a combination of pursuit and saccades

24
Q

What is the frontal eye field?

A

an area near the motor cortex that activates saccades via the reticular formation and/or the superior colliculus

25
Q

Who often gets internuclear ophthalmoplegia (INO)?

A

MS patients

26
Q

What is vergence?

A

moving the fovea to an object closer (convergence) or farther away (divergence)

27
Q

Interruption of the medial longitudinal fasciculus (MLF) can cause ______, called internuclear ophthalmoplegia (INO).

A

discoordination of medial and lateral recti muscles during horizontal gaze movements

28
Q

What are microsaccades?

A

the eye moving in small jumps to refresh the image several times/sec so it is never stabilized

29
Q

The medial longitudinal fasciculus (MLF) is especially vulnerable to interruption bc of _____.

A

its length

30
Q

Movement brings the fovea to an area that was being analyzed by _____.

A

that side of the brain

31
Q

More complex eye movements are programmed in specialized regions of ____.

A

the neocortex

32
Q

What muscles are responsible for horizontal rotation?

A

the lateral and medial rectus

33
Q

What CN innervates the lateral rectus?

A

CN6

34
Q

If the superior colliculus is damaged, ______.

A

saccades are less accurate and occur less often

35
Q

If the head continues to turn, the eyes rotate slowly until the limit of eye rotation is reached, then they _____.

A

snap quickly back to a new fixation point

36
Q

What are vergence movements?

A

eye movements in opposite directions

37
Q

What happens physiologically during the near/accommodation reflex?

A
  • contraction of the medial recti
  • pupil constriction
  • ciliary muscle constriction
38
Q

What are conjugate movements?

A

when both eyes move in the same direction

39
Q

Interruption of the medial longitudinal fasciculus (MLF) can cause discoordination of medial and lateral recti muscles during horizontal gaze movements, called ______.

A

internuclear ophthalmoplegia (INO)

40
Q

For stimuli moving faster than 50 degrees/second, a combination of _____ and ____ is used.

A

saccades and smooth pursuit

41
Q

Where is the blind spot located in the visual field?

A

15 degrees lateral

42
Q

These are rapid, ballistic eye movements (to bring an object onto the fovea).

A

saccades

43
Q

Where is the pattern generator for vertical saccades?

A

near the oculomotor nuclei

44
Q

Any stimuli that excites the abdences also excites the ____.

A

internuclear interneurons

45
Q

What are the 4 types of eye movements?

A
  1. smooth pursuit
  2. saccades
  3. vestibular ocular reflex (VOR) and optokinetic nystagmus (OKN)
  4. vergence
46
Q

When is nystagmus abnormal?

A

due to damage of the vestibular system or cerebellum

47
Q

What CN innervates the medial rectus?

A

CN3

48
Q

This is tracking to keep an object on the fovea.

A

smooth pursuit

49
Q

If BOTH the frontal eye field and the superior colliculus are damaged, _____.

A

there is a permanent loss of the ability to make saccades

50
Q

The eye moves in small jumps called _____.

A

microsaccades

51
Q

Voluntary eye movements are driven by the _____.

A

frontal lobes

52
Q

These eye movements are a combination of pursuit and saccades.

A

the vestibular ocular reflex (VOR) and optokinetic nystagmus (OKN)

53
Q

What do saccadic eye movements activate via the superior colliculus?

A

the brainstem gaze center (BGC)

54
Q

During conjugate gaze to the left, the left lateral rectus and the right medial rectus muscles are _____ and the left medial rectus and right lateral rectus are ______.

A

activated; inhibited

55
Q

What is smooth pursuit?

A

tracking to keep an object on the fovea

aNeuro Exam 3- Lindsey's (20 decks)

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