Disorders of the visual system

Question 1

Detection of light, localisation of objects, object identification, and what else are all features of normal vision?

Answer 1

Detection of movement

Question 2

The part of the eye that allows light to pass through to the retina:

Answer 2

Pupil

Question 3

The part of the eye that expands or contracts the pupil depending on the lighting:

Answer 3

Iris

Question 4

The central part of the macula, with the least distorted vision:

Answer 4

Fovea

Question 5

The internal lining of the eye which converts light into electrical impulses:

Answer 5

Retina

Question 6

The part of the eye that is made up of several retinal ganglion cells (RGC) which carries the electrical impulses from the retina to the brain:

Answer 6

Optic nerve

Question 7

The part of the retina that is specialised for central vision:

Answer 7

Macula

Question 8

The white of the eyes, each containing three pairs of extraocular muscles to allow the eyes to move:

Answer 8

Sclera

Question 9

Photoreceptors (including rods and cones), bipolar cells and retinal ganglion cells (RGC) make up which part of the eye?

Answer 9

Retina

Question 10

A type of photoreceptor that functions best in dim lighting conditions, found mostly in the periphery of the retina:

Answer 10

Rods

Question 11

A type of photoreceptor that functions best in ambient/high lighting conditions:

Answer 11

Cones

Question 12

The part of the cone that absorbs light energy and excites the rest of the cell:

Answer 12

Photopigment

Question 13

Explain the course of visual information in the retina:

Answer 13

Photoreceptors -> bipolar cells -> retinal ganglion cells -> optic nerve

Question 14

Axons of the retinal ganglion cells are called the optic nerves. After the optic chiasm, these nerves become:

Answer 14

Optic tracts

Question 15

The total amount of space that can be viewed by the retina:

Answer 15

Visual field

Question 16

____ optic nerve damage is likely to result in the loss of left peripheral vision:

Answer 16

Left

Question 17

Transection of the optic ___ is likely to lead to loss of vision in the bilateral periphery:

Answer 17

Chiasm

Question 18

Left optic ___ damage is likely to cause right hemianopia:

Answer 18

Tract

Question 19

As discussed in class, a patient experienced what visual deficit after developing an optic glioma?

Answer 19

Decreased acuity

Question 20

The retintotectal visual pathway:

Answer 20

Eye -> optic nerve -> optic chiasm -> optic tract -> superior colliculus

Question 21

The retinogeniculostriate visual pathway:

Answer 21

Eye -> optic nerve -> optic chiasm -> optic tract -> lateral geniculate nucleus (LGN) -> V1

Question 22

In the retinotectal pathway, the left visual hemifield projects to which part of the brain?

Answer 22

Right superior colliculus

Question 23

In the retinotectal pathway, the right visual hemifield projects to which part of the brain?

Answer 23

Left superior colliculus

Question 24

True or false: lesioning the superior colliculus completely inhibits eye movements toward contralesional targets.

Answer 24

False
(It doesn’t inhibit eye movement; only delays it.)

Question 25

What is the main target of the optic tracts?

Answer 25

Lateral geniculate nucleus (LGN) of the thalamus

Question 26

The left visual field projects onto which side of the lateral geniculate nucleus (LGN)?

Answer 26

Right

Question 27

The right visual field projects onto which side of the lateral geniculate nucleus (LGN)?

Answer 27

Left

Question 28

Where does visual information arrive in the retinogeniculostriate pathway once it has left the LGN of the thalamus?

Answer 28

Primary visual cortex/V1

Question 29

Cortical blindness in one side of the visual hemifield is called:

Answer 29

Hemianopia

Question 30

A blindspot in the visual field - either normal or pathological - is called a:

Answer 30

Scotoma

Question 31

Occurs when vision is lost in the middle of the visual field:

Answer 31

Macula sparring

Question 32

The part of the occipital lobe that contains a complete neural map of the retina:

Answer 32

Primary visual cortex/V1

Question 33

The primary visual cortex (V1) is located in which fissure?

Answer 33

Calcarine fissure

Question 34

In Rafal's (1990) study on residual vision without V1, patients were slower to respond to targets in the intact visual hemifield due to competing activation caused by a distractor stimulus in the retinotectal pathway (meaning they could still sense the distractor even though the opposite hemifield was impaired). This so-called "residual vision" was coined what?

Answer 34

Blindsight

Question 35

The ventral ("where") pathway projects to which part of the visual cortex?

Answer 35

V4

Question 36

The dorsal ("what") pathway projects to which part of the visual cortex?

Answer 36

V5

Question 37

Disorders caused by damage to the dorsal and ventral pathways are likely to have occurred in which vascular territory?

Answer 37

Posterior cerebral artery

Question 38

An impaired ability to become aware of multiple parts of a visual scene (i.e. not recognising more than one object at a time):

Answer 38

Simultaneous agnosia

Question 39

Impaired depth perception is a disorder caused by damage to the ___ ("where") pathway:

Answer 39

Dorsal

Question 40

An inability to recognise colours due to disruption in colour processing:

Answer 40

Achromatopsia

Question 41

True or false: achromatopsia is characterised by an inability to name colours when visually and verbally represented.

Answer 41

False (People with achromatopsia can name colours when described to them, but not presented visually).

Question 42

Difficulty naming objects based on visual information alone:

Answer 42

Object agnosia

Question 43

An inability to recognise faces, usually resulting from bilateral lesions:

Answer 43

Prosopagnosia