Eye Movements and Visual System Neuro Review

Question 1

For performing ocular motility, there are 4 ___ muscles and 2 ___ muscles. Where does each type of muscle insert on the eye?

Answer 1

4 rectus muscles, which insert anteriorly in the sclera

2 oblique muscles, which insert posteriorly in the sclera

Question 2

What are the two centers for conjugate gaze located in the BRAINSTEM?

Answer 2

Rostral interstitial nucleus (vertical gaze center)

PPRF (horizontal gaze center)

Question 3

The rostral interstitial nucleus is the _____ gaze center

Answer 3

Vertical gaze center

Question 4

The PPRF is the ____ gaze center

Answer 4

Horizontal gaze center

Question 5

What are the two centers for conjugate gaze located in the CORTEX?

Answer 5

Frontal eye field

Occipital eye field

Question 6

What is the function of the frontal eye field?

Answer 6

Brings an object onto the fovea

Initiates saccadic eye movements

Question 7

What is the function of the occipital eye field?

Answer 7

Keeps an object on the fovea

Needed for smooth pursuit

Question 8

What is the Vestibuloocular reflex?

Answer 8

Compensatory eye movements in OPPOSITE direction from head movements, relying on vestibular input

Stabilizes image on the retina during rotation of the head

Question 9

What are vergence movements of the eye?

Answer 9

Accommodation signals used to guide vergence eye movements with CN III and the Medial Rectus muscles

Question 10

Describe the pathway for activating volitional saccadic movements to your left

Answer 10

R frontal eye field is activated –> activates L PPRF to activate the L abducens nucleus (for the L lateral rectus m) and the R oculomotor nucleus (for the R medial rectus m)

Question 11

What are the two kinds of ophthalmoplegia?

Answer 11

Internuclear ophthalmoplegia

Gaze palsy

Question 12

Where is the lesion in Internuclear Ophthalmoplegia?

Answer 12

MLF lesion
(Remember, MLF is the fiber path containing axons to connect the different nuclei of EOMs for horizontal or vertical gaze)

Question 13

Where is the lesion in Gaze Palsy?

Answer 13

PPRF lesion–horizontal gaze center

Both eyes cannot move together in one direction, but they move normally in the other direction

Question 14

What are the main differences between Rods and Cones?

Answer 14

Rods- monochromatic; better for detecting motion; Night vision

Cones- Color vision; 3 types of color pigment (R, G, B); Work more in the daytime

Question 15

Where does the first action potential occur detecting light?

Answer 15

Ganglion cells.

There are no action potentials in the photoreceptors!

Question 16

How does light reach the photoreceptors?

Answer 16

Pass through pupil, reach the retina and passes through the ganglion cells and interneurons before reaching the photoreceptors

Question 17

Describe the fovea’s anatomy and function

Answer 17

There are only cones at the fovea, so it has the highest visual acuity and best color vision

It is avascular and the ganglion cells and interneurons are pushed off to the side

Question 18

Describe the pathway from the ganglion cells in the eye back to the occipital lobe

Answer 18

Nasal fibers cross at the optic chiasm. Temporal fibers do not.

Go back to the lateral geniculate nucleus, synapse, and then travel through optic radiations (either through parietal lobe or temporal lobe) to the occipital lobe

Question 19

What are the two type of ganglion cells? What kinds of photoreceptors are they associated with?

Answer 19

M type
Assoc w/ RODS
Magnocellular layer distirbution
Motion

P type
Assoc w/ CONES
Koniocellular distribution
Color and High detail

Question 20

The optic nerve sends most of its fibers to the lateral geniculate nucleus, but some go to other areas, such as…? What for?

Answer 20

Pretectal area (for pupillary reflexes)

Superior Colliculus (for head and eye movements)

Question 21

The optic radiations traveling from the lateral geniculate n. to the occipital lobe travel through which lobes of the brain?

Answer 21

Parietal lobe (upper fibers capturing vision from the LOWER visual field)

Temporal lobe (Meyer’s loop– lower fibers capturing vision from the UPPER visual field)

Question 22

A full lesion of the R optic nerve would cause…

Answer 22

R eye blindness

Question 23

A full lesion of the optic chiasm would cause…

Answer 23

Bitemporal hemanopsia

Question 24

A full lesion of the R lateral geniculate nucleus would cause…

Answer 24

L homonymous hemanopsia

Question 25

A lesion of the optic radiations in Meyer’s loop would cause…

Answer 25

L homonymous upper quadrantinopia (pie in the sky)

Question 26

A full lesion of the optic radiations traveling to the R occipital lobe would cause…

Answer 26

L homonymous hemanopsia with macular sparing

Question 27

3 Classic symptoms of Horner’s Syndrome

Answer 27

Ptosis
Miosis
Anhydrosis

Question 28

When shining light into an eye to test the pupillary response, the info is transmitted to the pretectal area, then the______?

Answer 28

Edinger Westphal Nucleus

Question 29

What two cranial nerves are involved in the Blink (Corneal) Reflex?

Answer 29

CN V – afferent

CN VII – efferent

Question 30

Which layer of the cortex is greatly expanded in the occipital lobe?

Answer 30

Layer 4

Question 31

In cortical processing of visual information, the Parietal lobe tells you….?

Answer 31

Where is an object in space?

Question 32

In cortical processing of visual information, the Temporal lobe tells you….?

Answer 32

What an object is