Visual Tracts

Question 1

Distinguish between the binocular zone and the monocular zones.

Answer 1

Binocular zone is the broad central area seen by both eyes.

Monocular zones are seen with only the corresponding eye.

Question 2

How is an image oriented to the eye?

Answer 2

It is rotated 180 degrees.

Question 3

Which side do temporal and nasal go to? Contralateral or ipsilateral

Answer 3

Temporal will stay on the ipsilateral side, nasal will travel to the contralateral side.

Question 4

Where do the optic tract nerves terminate?

Answer 4

Lateral geniculate nucleus.

Question 5

What are the two layers of the Lateral Geniculate Nucleus?

Answer 5

Magnocellular and Parvocellular layers.

Question 6

What is the function of the Magnocellular layers? What is it sensitive to?

Answer 6

Large receptive fields with rapidly conducting axons that are sensitive to moving stimuli

Question 7

What is the function of the Parvocellular layers? What is it sensitive to?

Answer 7

Smaller receptive field with slower conducting axons, sensitive for stationary stimuli with high acuity color.

Question 8

What layers do the Magno and Parvo cells occupy respectively?

Answer 8

Magno- 1 & 2

Parvo- 3-6

Question 9

What layers are present on the temporal layer (magno and parvo cells) and where do they synapse?

Answer 9

Layers 235 and they synapse on the ipsilateral lateral geniculate nucleus

Question 10

What layers are present on the nasal retina (Magno and Parvo cells) and where do they synapse?

Answer 10

Layers 146 and they synapse on the contralateral lateral geniculate nucleus

Question 11

Where do the secondary neurons from the Lateral geniculate nucleus synapse?

Answer 11

Along the banks of the calcarine sulcus

Question 12

Why could an injury to the temporal lobe cause superior visual field loss?

Answer 12

Meyer’s Loop

Question 13

If a dog is seen in the inferior visual field on the left, where will it travel to in the brain?

Answer 13

Anterior superior bank of the calcarine sulcus.

Question 14

Where is the macula information represented in Brodmann’s area 17 compared to peripheral fields?

Answer 14

More posteriorly.

Question 15

What areas is the striate cortex represented in?

Answer 15

18 and 19

Question 16

What is the function of Areas 18 and 19?

Answer 16

Visual association cortex

Question 17

What is the superior colliculus important for with eye movements?

Answer 17

Directing eye movements

Question 18

What is the Pretectal area important for with eyes?

Answer 18

Facilitates the pupillary light reflex

Question 19

Explain the steps of pupillary constriction reflex.

Answer 19

Retinal axons to pretectal area, bilateral projections sent through the posterior commissure to the edinger Westphal nucleus, PSymp exit with CN3 and synaps on short ciliary nerves to constrict pupil

Question 20

Explain what congruous deficits are with the visual field.

Answer 20

When the visual loss of one eye can be superimposed on the other side.

Question 21

Where will damage anterior to the optic chiasm localize to?

Answer 21

Ipsilateral eye

Question 22

What will damage at the chiasm cause? (Like pituitary adenoma)

Answer 22

Heteronymous deficit, so most commonly will cause bitemporal hemainopia

Question 23

What will damage behind the chiasm cause?

Answer 23

Homonymous deficits, so the complete loss of vision on both eyes on the same side. (Lose right temporal and right nasal fields with a lesion of both of the optic radiations.