Visual System Pathways

Question 1

What part of the thalamus do the cranial tracts terminate?

Answer 1

LGN (lateral geniculate nucleus)

Question 2

What “Area” is the primary visual cortex?

Answer 2

Area 17

Question 3

What “Areas” are the visual association cortex?

Answer 3

Areas 18 and 19

Question 4

How many neurons does it take to get from the eye to the LGN?

Answer 4

3

Question 5

What are the 1˚, 2˚, and 3˚ afferents from the eye?

Answer 5

1˚: receptors
2˚: bipolar cells
3˚: ganglion cells

Question 6

Which cells form the optic nerve?

Answer 6

ganglion cells (3˚ retinal cells)

Question 7

What are the two types of visual fields?

Answer 7

retinal and visual

Question 8

Images are both ______ and ______

Answer 8

inverted and flipped

Question 9

The optic nerve is an outgrowth of which embryological structure?

Answer 9

diencephalon

Question 10

The optic chiasm sits on what cranial structure?

Answer 10

sella turcica

Question 11

What structure is located immediately behind the optic chiasm

Answer 11

pituitary gland

Question 12

The optic tract carries information from the contralateral/ipsilateral visual field

Answer 12

contralateral

Question 13

What is retinotopic organization?

Answer 13

lower visual field located more medially

Question 14

What is the name of the fiber bundle that runs from the LGN?

Answer 14

optic radiation

Question 15

The sublenticular portion of the optic radiations carries 4˚ neuron fibers from what visual field?

Answer 15

upper visual field

Question 16

The retrolenticular portion of the optic radiations carries 4˚ neuron fibers from what visual field?

Answer 16

lower visual field

Question 17

What type of defect can occur after damage to either the sublenticular or retrolenticular lateral geniculate nucleus?

Answer 17

loss of 25% of visual field

Question 18

The sublenticular optic tract carries axons to what structure?

Answer 18

lingual

Question 19

The retrolenticular optic tract carries axons to what structure?

Answer 19

cuneate

Question 20

The dorsal stream of the association visual cortex runs through what portion of the brain?

Answer 20

parietal/temporal cortex

Question 21

The dorsal stream of the association visual cortex is responsible for what type of processing?

Answer 21

where?

Question 22

The ventral stream of the association visual cortex runs through what portion of the brain?

Answer 22

inferior temporal cortex

Question 23

The ventral stream of the association visual cortex is responsible for what type of processing?

Answer 23

what?

Question 24

What is a homonymous defect?

Answer 24

either right or left visual field affected

Question 25

Where is a homonymous defect usually located?

Answer 25

almost exclusively after the optic chiasm

Question 26

Where is a heteronymous defect usually located?

Answer 26

almost exclusively at the optic chiasm

Question 27

What is a heteronymous defect?

Answer 27

involves parts of both visual fields