Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL21332 - Motor Systems > Lecture 16 - Occulomotor Systems > Flashcards

Lecture 16 - Occulomotor Systems Flashcards

1
Q

What are the two main reseaons we move our eyes? [2]

A
  • To look at something

- To track something

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the five types of eye movement? [5]

A
  • Saccades
  • Smooth pursuit movements
  • Vergence eye movements
  • Vestibulo-ocular movements
  • Optokinetic movements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are saccades?

A

Shifting the fovea to a peripheral target

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are Smooth pursuit movements?

A

Keeping the images of a moving target on the fovea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are Vergence eye movements?

A

Moving the eyes in opposite directions so an image is on both foveae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are Vestibulo-ocular movements?

A
  • Keeps image on retina during brief head movements

- Driven by the vestibular system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are Optokinetic movements?

A
  • Keeps image on fovea during sustained head movements

- Driven by visual stimulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Saccades are very […].

A

Fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What can we change about a saccade?

A
  • Direction

- Aplitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What direction does Abduction rotate the eye?

A

Away from the nose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which direction does Adduction rotate the eye?

A

Towards the nose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which direction does Elevation rotate the eye?

A

Vetically up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which direction does Depression rotate the eye?

A

Veritcally down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which direction does Intorsion rotate the eye?

A

Rotates top of cornea towards the nose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which direction does Extorsion rotate the eye?

A

Rotates top of cornea away from the nose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the six muscles that move the eye? [6]

A
  • Superior rectus
  • Inferior rectus
  • Medial rectus
  • Lateral rectus
  • Superior oblique
  • Inferior oblique
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which muscle is responsible for adduction of the eye?

A

Medial rectus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which muscle is responsible for abduction of the eye?

A

Lateral rectus

19
Q

What happens to individuals with lesion on extraocular muscles/nerves?

A
  • Suffer double vision

- Image is no longer on the same point of both fovea

20
Q

What are the three cranial nerves that control the extraocular muscles? [3]

A
  • The abducens nerve (CN VI)
  • The occulomotor nerve (CN III)
  • The trochlear nerve (CN IV)
21
Q

What is the relationship between eye velocity and extraocular motor neuron firing rate?

A

As the velocity increases the firing rate also increases

22
Q

What happens once the eye has reached its desired position?

A

It is held in place by contraction of the extraocular muscles

23
Q

Where do the motor circuits for saccades reside?

A

In the brain stem

24
Q

Where is the horizontal component of a saccade located?

A

In the pons and meddula

25
Q

Where is the vertical component of the saccade loacted?

A

In the mesencaphaluc reticular formation (in midbrain)

26
Q

What does the pulse part of the step-pulse signal show?

A

The speed of the saccade

27
Q

What does the step part of the step-pulse signal show?

A

The extent of the saccade

28
Q

Whcih neurons give rise to the pulse component?

A

Burst cells

29
Q

What is the role for medium-lead burst cells?

A

Making direct conections to the motor neurons

30
Q

What is the role for long-lead burst cells?

A
  • Driving medium-lead burst cells

- Recieving inputs from higher centres

31
Q

What is the role for inhibitory burst cells?

A
  • Supressing contralateral abducens neurons and excitatory burst neurons
  • Driven by medium-lead burst cells
32
Q

What is the role for Omnipause cells?

A

They inhibit burst neurons

33
Q

How do omnipause cells work?

A
  • Fire continuosly

- Stop firing around the time of a saccade

34
Q

Which parts of the brain stem is responsible for maintaining a signal relating to eye position? [2]

A
  • Medial vestibular nucleus

- Nucleus prepositus hypoglossi

35
Q

What are saccades controlled by?

A

The cerebral cortex

36
Q

What controls the output for the pontine and mescenphalic burst cells?

A

The superior colliculus

37
Q

What are the two function regions of the superior colliculus? [2]

A
  • Superficial layers

- Intermediate & Deep layers

38
Q

Where do the superficial layers recieve input from?

A
  • Retina

- Primary visual cortex

39
Q

The activity in neurons of the intermediate and deep layers is related to what?

A

Occulomotor actions

40
Q

What affect do the basal ganglia have on the super colliculus?

A

They send powerful inhibitory signals

41
Q

What is the role of Frontal eye field neurons?

A
  • They excite movement related neurons in the intermediate layers of the supper colliculus
  • Inhibit the inhibitory projection from the basal ganglia
42
Q

Where are the neurons that are responsible for smooth pursuit located? [3]

A
  • The medial vestibular nucleus
  • The nucleus prepositus hypoglossi
  • The pons
43
Q

Which muscles control vergence?

A

The horizontal rectus muscles

44
Q

Which neurons control vergence?

A

Neurons in the occulomotor nucleus of the midbrain

BIOL21332 - Motor Systems (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions