Neuro: Visual System

Question 1

Lesions to the retina and optic nerve produce unilateral damage UNLESS the damage is where?

Answer 1

The junction of the optic nerve and optic chiasm

Question 2

What defects do medial chiasm lesions produce?

Answer 2

Bilateral defects

Question 3

What defects for lateral chiasm lesions produce?

Answer 3

Unilateral defect unless there is damage on both sides (laterally)

Question 4

What is the retinotopic map and what is its importance?

Answer 4

The retinotopic map shows the precise arrangement of photoreceptors and retinal receptive fields and are used to determine lesion locations based on VF

Question 5

What is the “what” pathway involved with?

Answer 5

Form and color

Question 6

What is the “where” pathway involved with?

Answer 6

Motion and spatial analysis

Question 7

What is the function of the suspensory ligament of the lens (zonule of zinn)?

Answer 7

Aid in focusing on near and far objects

Question 8

What is retinitis pigmentosa (very general)?

Answer 8

Rod cells lose their function and over time can cause complete blindness by affecting both rods and cones but the pupillary light reflex remains

Question 9

What is one of the main features seen in patients that can increase their risks of AMD?

Answer 9

Drusen

Question 10

What does damage to the retina often cause?

Answer 10

A scotoma

Question 11

What artery aneurysm can cause damage to the lateral optic chiasm?

Answer 11

Internal carotid artery

Question 12

Damage in what location can mimic the defects seen in a lateral optic chiasm lesion?

Answer 12

Damage to the lateral optic nerve

Question 13

Damage to the medial optic chiasm is most often due to a pituitary gland tumor, but can also be due to an aneurysm of which artery?

Answer 13

Anterior communicating artery aneurysm

Question 14

Which artery causes a lesion in the optic tract?

Answer 14

Occlusion of the anterior choroidal artery

Question 15

If there is damage to the LGN, what artery is likely responsible?

Answer 15

An occlusion of the posterior choroidal artery

Question 16

If the VF looks like this on both eyes, what artery is causing the defect, and to which region?

Answer 16

Posterior choroidal artery, LGN

Question 17

If the VF looks like this in both eyes, which artery is causing the defect, and to which region?

Answer 17

Anterior choroidal artery, LGN

Question 18

If pt has loss of vision in one eye, and full vision in the other, where is the defect likely located?

Answer 18

The optic nerve

Question 19

If the pt presents with a binasal hemianopsia, where is the damage likely located?

Answer 19

Lateral optic chiasm

Question 20

If a pt presents with a bitemporal hemianopsia, where is the issue likely occurring?

Answer 20

Medial optic chiasm

Question 21

If a pt has loss of half of the right VF in both eyes, where is the issue likely located?

Answer 21

Could be the optic tract or LGN (said we should consider it to just be LGN issues for our cases)

Question 22

What is the magnocellular system?

Answer 22

The “where” system, located mostly in the periphery and responsible for motion and gross spatial features

Question 23

What is the parvocellualr system?

Answer 23

The “what” system located mostly central and is responsible for distinguishing form and color

Question 24

What layers of the LGN do the magnocellular system project to?

Answer 24

1 and 2

Question 25

What layers of the LGN does the parvocellular system, project to?

Answer 25

Layers 3-6

Question 26

What is the retinotectal projection responsible for?

Answer 26

The pupillary light reflex

Question 27

Where is the retinohypothalamic projections and what is it responsible for?

Answer 27

Suprachiasmatic nucleus, pupillary dilation

Question 28

What are the retinocollicular projections and what are they involved with?

Answer 28

Projections to the sueprior colliculus, visual reflexes

Question 29

Superior radiations are responsible for which region in the VF?

Answer 29

Inferior VF

Question 30

Superior radiations run through the ___________ lobe and pass the _________ and end in the ____________________

Answer 30

Parietal lobe, cuneus, superior calcarine sulcus

Question 31

Inferior optic radiations are responsible for which region of the VF?

Answer 31

Superior visual field

Question 32

Inferior radiations run through the _______ lobe and end in the ____________

Answer 32

Temporal lobe, inferior calcarine sulcus

Question 33

Myers loop is involved with which optic radiation and lobe? Damage will cause what?

Answer 33

Inferior radiations, temporal lobe, loss of contralateral superior VF

Question 34

Baums loop is involved with which radiation and rings through which lobe? Damage will cause what?

Answer 34

Superior radiations, parietal lobe, contralateral inferior VF

Question 35

Infarct to the middle cerebral artery can affect which regions?

Answer 35

LGN, optic tract, and radiations

Question 36

Damage to the posterior cerebral artery often causes what VF defect?

Answer 36

Contralateral homonymous hemianopia with macular sparing

Question 37

What causes the macula to be spared?

Answer 37

Dual perfusion by posterior cerebral artery and middle cerebral artery

Question 38

Does ventral stream damage affect the what or the where?

Answer 38

The what

Question 39

Does dorsal stream damage affect the what or the where?

Answer 39

The where

Question 40

What happens in people with damage to the “what”?

Answer 40

They cannot recognize objects but they can appropriately coordinated their movements to pick the object up

Question 41

What happens in people with damage to the “where”?

Answer 41

They can recognize objects but are unable to pick them up

Question 42

What is homonymous hemiachromatopia and what area is affected?

Answer 42

Contralateral color blindness, ventromedial occipital cortex

Question 43

What is homonymous hemikinetopsia and where is the damage?

Answer 43

Contralateral motion blindness, parietal-occipital-temporal area

Question 44

What is prosopagnosia and where is the damage?

Answer 44

Inability to recognize faces, occipitotemporal/fusiform gyrus

Question 45

When there is damage to the right parietal cortex after MCA lesion, what often happens?

Answer 45

Left neglect

Question 46

What is neglect?

Answer 46

When a patient will suppress or neglect part of an image due to in the brain

Question 47

When does right neglect occur?

Answer 47

Only in severe cases