Visual Perception Flashcards

1
Q

What did we study in relation to the structure of the eye?

A

The lens
The retina
Ganglion cells

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2
Q

What was studied in relation to depth perception?

A

Monocular cues

Binocular depth perception

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3
Q

What was studied in relation to vision in the brain?

A

Lateral geniculate nuclei
The primary visual cortex
Development of binocular stereopsis

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4
Q

Where are rods and cones located?

A

In the retina

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5
Q

What muscle controls the lens?

A

The cilary muscle

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6
Q

What is the soft outer coating of the eyeball called?

A

The cornea

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7
Q

What is the point of central focus called?

A

The fovea

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8
Q

What is the path of light through the different parts of our eye?

A

Cornea > pupil > lens > retina

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9
Q

What does the iris do?

A

Expand and contract the pupil to regulate the amount of light that can enter

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10
Q

When the target is near in focus the lens is __________ and _______ and the iris ________.

A

Shorter and thicker

Expands

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11
Q

When the target is further away in focus the lens is __________ and _______ and the iris ________.

A

Taller and thinner

Contracts

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12
Q

What is near sightedness called?

A

Myopia

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13
Q

What is far sightedness called?

A

Hyperopia

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14
Q

What is myopia?

A

When the light doesn’t reach the retina (focused too early)

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15
Q

What is hyperopia?

A

When the light goes beyond the retina (focuses too late)

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16
Q

What can you use to correct myopia?

A

Concave lenses

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17
Q

What can you use to correct hyperopia?

A

Convex lenses

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18
Q

What is the retina?

A

The light sensitive membrane at the back of the eye that contains photoreceptors

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19
Q

What is the blind spot?

A

Where the optic nerve exits the eye (on the retina)

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20
Q

How many photoreceptors does the retina contain?

A

100 million

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21
Q

What are the two types of photoreceptors?

A

Rods and cones

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22
Q

What are cones responsible for?

A

Daylight vision
Colour
Visual acuity

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23
Q

Where are cones located?

A

At the centre of the foveal

Less near the periphery

24
Q

Each cone cell synapses onto its own ?

A

ganglion cell

25
Q

What are rods responsible for?

A

Night vision

Periphery vision

26
Q

More than one rod converges onto the same ganglion cell. How does this affect our vision?

A

Less precision

More sensitively to light (when there isn’t much) so we can see in the dark

27
Q

What is a ganglion cell?

A

A retinal cell that receives visual information from photoreceptors and transmits to the brain

28
Q

What was studied in relation to visual perception?

A

The structure of the eye
Depth perception
Vision in the brain

29
Q

How many ganglion cells are there?

A

100x fewer than photoreceptors

30
Q

How often do ganglion cells fire?

A

Spontaneously at a regular resting rate

31
Q

When does the firing rate change of a ganglion cell?

A

When light hits it’s receptive field

32
Q

What are the receptive fields of a ganglion cell called?

A

Centre-surrounded and either:
On-centre
Off-centre

33
Q

What’s the difference between on- centre and off-centre ganglion cells?

A

On-centre: when light hits the middle firing rate is FACILITATED
Off-centre: when light hits the middle firing rate is INHIBITED

34
Q

What is the grid (visual illusion) called where you can see black dots in the intersections between a grid of black boxes?

A

Germans grid

35
Q

What two processes give us 3D vision?

A

Monocular depth cues

Binocular depth perception

36
Q

What are 6 monocular depth cues?

A
Occlusion 
Relative size and position 
Height cues 
Aerial perspective (haziness) 
Linear perspective 
Accommodation
37
Q

What is occlusion?

A

Assuming things are further away when they are behind

38
Q

What is accommodation?

A

When something is blurry it can be assumed it’s super close or super far away

39
Q

What is binocular disparity?

A

Not receiving the same information from both eyes because each has slightly different visual fields

40
Q

What is it called when can perceive depth because of binocular vision?

A

Stereopsis

41
Q

What is the size of the angle both eyes can see at the same time?

A

110-120 degrees

42
Q

The circle which can be drawn between the focal point and the sides of our eye when focusing is called the?

A

Horopter (or the Vieth Mueller Circle)

43
Q

What is said about any point that falls on the Horopter?

A

It will cast the same image on one retina as it does on the other

44
Q

When the object is closer than the Horopter it is called ?

A

Crossed disparity

45
Q

When the object is further away than the Horopter it is called ?

A

Uncrossed disparity

46
Q

What is used in binocular stereopsis to determine the depth?

A

Disparity magnitude (crossed = less disparity, or uncrossed = more disparity)

47
Q

What is the effective that happens with your eyes when disparity is either crossed or uncrossed.

A

Crossed disparity = cross eyed = 3D

Uncrossed disparity = parallel viewing = 3D

48
Q

What is it called when you see 3D images from either parallel viewing or viewing two similar, adjacent images cross eyed?

A

Free fuse

49
Q

When each eye revives two different kinds of information, which stimuli is more likely to be dominant?

A
More interesting stimuli: 
More salient (brighter, more contrast, moving) 
More meaningful
50
Q

What does LGN stand for?

A

lateral geniculate nuclei

51
Q

What does the LGN do?

A

All 4 LGNs act as relay stations from the eye to the cortex (each responsible for one half of each eye)

52
Q

What does each side of the visual cortex process?

A

Left visual cortex = processes right visual field

Right visual cortex = processes left visual field

53
Q

So both LGN axons cross sides?

A

No, the axons closest to the nose cross but the axons closest to the ears don’t cross

54
Q

What is cortical magnification?

A

Where the information coming from near the fovea is given more space in the brain than the periphery is given for processing

55
Q

When does binocular vision develop?

A

3-5 months