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PSYC 2390 Midterm 1 > Lecture Set 2 > Flashcards

Lecture Set 2 Flashcards

1
Q

Disorders/problems associated with the retina?

A
  1. detached retina
  2. floaters
  3. diabetic retinopathy
  4. macular degeneration
  5. cone dystrophy
  6. retinitis pigmentosa
  7. glaucoma
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2
Q

What is diabetic retinopathy?

A
  • as a result of diabetes
  • blood vessels in eye start to swell, weaken and leak –> drops of blood/tissue in vitreous humour –> floaters
  • retina is starved of nutrition = neovascularization
  • more floaters –> even retinal attachment –> blindness
  • higher risk for cataracts and glaucoma
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3
Q

What is neovascularization?

A

when the retina is starved of nutrition/blood

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4
Q

What can be used to slow the diabetic retinopathy process down?

A

Laser photocoagulation

- aim at leaky vessels to seal them off

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5
Q

What can be used in serious cases of diabetic retinopathy?

A

pan retinal photocoagulation

  • retina is demanding so much blood, blood vessels can’t keep up
  • used to deliberately damage retina
  • creates thousands of tiny blind spots so retina doesn’t demand so much blood
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6
Q

What is type 1 diabetes?

A

insulin resistance; associated with aging and lifestyle

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7
Q

What is type 2 diabetes?

A

from childhood; lack insulin

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8
Q

What is macular degeneration?

A

Loss of 5mm in very centre of the fovea
- age related

2 kinds:

  • dry macular degeneration
  • wat macular degeneration
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9
Q

What is the macula?

A

centre of the fovea

- allows fine, detailed vision

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10
Q

What is dry macular degeneration?

A 
yellow lumps (drusen) develop in the macula, causing cone death in that area (because they are pushing them away from the source of nourishment) 
- develops slowly, gradually
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11
Q

What is wet macular degeneration?

A

Drusen grows in, but neovascularization at the same time

- occurs rapidly

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12
Q

Treatment of macular degeneration?

A
  • laser photocoagulation

- certain dietary changes (beta carotene, zinc, vitamin C)

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13
Q

Methods of testing for macular degeneration?

A

Amsler grid

Looks like graph paper –> fixate on centre dot

  • normal vision = see square boxes
  • abnormal vision = wavy lines around centre
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14
Q

What is cone dystrophy?

A

The body doesn’t produce enough of certain protein –> loss of cones (rods are fine)

  • deterioration noticeable in fovea
  • problems with colour vision and fine detail (difficulty distinguishing)
  • performance in low lighting is quite good
  • during the day = too bright; can’t see detail

Two kinds:

  • progressive
  • static
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15
Q

What is progressive cone dystrophy?

A

can occur at anytime

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16
Q

What is static cone dystrophy?

A

seen in adolescents

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17
Q

What is retinitis pigmentosa?

A

Hereditary retinal disorder

  • differs from macular degeneration because it occurs in adolescence
  • loss of rods
  • works from outside of eye in (developing tunnel vision), until only have functional fovea
  • trouble with night vision = night blind
  • rods = most of visual system (so this isn’t good)
  • problem with pigment epithelium, but affects rods first
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18
Q

What is glaucoma?

A

Associated with older age
- involves vent which allow aqueous humour to bathe cornea and lens (provides nourishment)

Two kinds:
- open and closed angle

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19
Q

What is open angle glaucoma?

A

Emerges so slowly, people don’t even know they’re getting it

Fluid gets blocked so it can’t get out –> build up of fluid pressure against corner and then back of eye –> injure retina –> pinch off ganglion cells (axons) –> causes blind spots

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20
Q

What can be used to cure open angle glaucoma?

A
  • blood pressure medications

- cannabis - beneficial in ocular fluid pressure

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21
Q

What is closed angle glaucoma?

A

Develops very rapidly

Blockage –> iris flops over –> touches lens –> tiny area for fluid pressure to develop –> aqueous humour can’t get out (pupillary block)

can quickly become blind
- can occur early in life; often first thing in the morning

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22
Q

Symptoms of closed angle glaucoma?

A

blurred vision, nausea

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23
Q

What can be used to fixed closed angle glaucoma?

A

Iridectomy - make a small hole in the iris so fluid can get out (reduces pressure)

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24
Q

Who are more at risk for glaucoma?

A

People who are farsighted (axial hyperopia) - eyeballs are shortened (less room)

Orientals

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25
Q

What does transduction require?

A

Photo-pigments

  • retinal
  • opsin
  • -> when they break apart = bleaching –> action potential
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26
Q

Which photo-pigment is associated with rods?

A

rhodopsin

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27
Q

What absorbs more like - black or white?

A

black absorbs a lot of light

white reflects a lot of light

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28
Q

what is an after image?

A

end up seeing the opposite of what you just looked at

- one type of after effect

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29
Q

What is the reasoning behind an after image?

A

When you see white - a lot of photo-chemical are used up, and there are a lot of action potentials = neurons fatigue

When you see black - not a lot of light is reflected to eye, eye doesn’t tire

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30
Q

What is the role of collector cells?

A

To summarize information

- 126 million –> 1 million

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31
Q

What is convergence?

A

a lot of different cells converge to one neuron (adds up activity)

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32
Q

What is lateral summation?

A

side by side

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33
Q

What is the effect of convergence on rods?

A

makes them more sensitive

- can see really well in dim light

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34
Q

Do cones converge?

A

No, they have their own retinal ganglion cell

- allows for fine detail

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35
Q

What is lateral inhibition?

A

Side by side inhibition

  • lowers activity
  • allows us to see differences in brightness
  • gives u acuity (accuracy and ability to see fine detail)
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36
Q

What is maternal inhibition Important for?

A
  • recognizing objects

- visual motor coordination

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37
Q

Which illusions are a result of lateral inhibition?

A

Mach bands, herman grid, simultaneous contrast

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38
Q

What is the reasoning behind mach bands?

A

Due to abrupt or gradual changes in brightness

- visual system is exaggerating differences in brightness

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39
Q

What was the horse shoe crab (Limulus) used to explain?

A

Simplified version of the human retina

  • ommatidium = combination of lens and retina together
  • lateral plexus = different axons extending between ommatidium
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40
Q

What is the reasoning behind Herman’s grid?

A

The white areas produce many APs –> a lot of inhibitory neurotransmitter = intersections look darker

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41
Q

What is the reasoning behind simultaneous contrast?

A

Occurs when our perception of the brightness or colour of one area is affected by the presence of an adjacent or surrounding area

  • lateral inhibition can’t be the only story behind this illusion
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42
Q

What is the only way of knowing if something is in a cell’s receptive field?

A

Look at how many APs are produced

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43
Q

What is the response of an on response?

A

+ activity

- when the cell has light on it –> produces more AP/second than spontaneous activity

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44
Q

What is the response of an off response?

A
  • activity

- when the cell has light on it –> produces less AP/second than spontaneous activity

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45
Q

What is the result of something that is not in cell’s receptive field?

A

AP = spontaneous activity

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46
Q

What is circular center surround?

A

Cell responds in opposite ways depending on where the light falls in receptive field

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47
Q

What is the result of an on center/off surround?

A
  1. white or black light fully covering –> spontaneous activity
  2. black center, white surround –> fewest APs
  3. white center, black surround –> most APs
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48
Q

What is the result of an off center/on surround?

A
  1. white or black light fully covering –> spontaneous activity
  2. black center –> most APs
  3. White center –> fewest APs
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49
Q

Two types of retinal ganglion cells?

A

Parvo and Magno

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50
Q

What are parvo retinal ganglion cells?

A

SMALL

  • 80% of cells
  • thin axons = slow transmission of information
  • gives fine detail and colour
  • hard to bore = sustained response
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51
Q

What is sustained response?

A

Tends to keep responding for a period of time when stimulus is there

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52
Q

What are mango retinal ganglion cells?

A

LARGE

  • 10% of cells
  • extensive branching
  • rapid transmission of information
  • responds to brightness
  • colour blind and lacks fine detail
  • transient responding
  • sensitive to motion
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53
Q

What is a transient response?

A

Responds best when things don’t stay the same (looking for change across time)

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54
Q

What is fixation?

A

Looking straight at something

- involves left and right visual fields

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55
Q

Where does information from the right visual field go?

A

Left side of the brain

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56
Q

Where does information from the left visual field go?

A

Right side of the brain

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57
Q

What does the term retinotopic mean?

A

The positions of the real image are preserved in the brain’s representation

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58
Q

What does feed-forward mean?

A

Eye –> brain
AKA bottom up processing
- taking information progressively to deeper levels of the brain

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59
Q

What does feed-back mean?

A

Communication to lower levels of the brain

AKA top down processing = expectations and beliefs driving what you see

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60
Q

what is coding?

A

How the brain signals information

- depends on line orientation

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61
Q

What is specificity coding?

A

respond to one type of stimulus

  • one cell for one attribute
  • if you lose this type of cell –> can no longer see this
  • further back in brain
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62
Q

What is distributed coding?

A

don’t look at just one cell to find out presence of vertical line, but at a pattern of activity across many cells

  • every cell will respond to a certain extent to a certain stimulus
  • some respond better than others (more APs/sec)
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63
Q

Looking at AP/second tells us?

A

about brightness and how similar stimulus is to that that the cell is tuned to

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64
Q

True or false - the tilt after effect is an after effect but not an after image?

A

True

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65
Q

Explain the tilt after effect

A

When a person stares at tilted lines for a period of time –> become adapted
- show vertical lines –> they report seeing tupped lines in the opposite direction of those they adapted to = compromised vertical lines

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66
Q

Where do cells come together in the retina?

A

optic chiasm = intersection

- causes left visual info –> right side of brain and right visual info –> left side of brain

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67
Q

Where do fibres on nasal side lead?

A

cross over in both eyes

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68
Q

Where do fibres on temporal side lead?

A

they go straight back

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69
Q

True or false - it is the visual field which crosses over and not the eyes?

A

True

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70
Q

what structure is located just about the optic chiasm?

A

Supra-chiasmatic nucleus

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71
Q

What is the role of the Supra-chiasmatic nucleus?

A

governs circadian rhythm

- assesses level of light that comes into eye

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72
Q

Where does the Supra-chiasmatic nucleus send incoming info?

A

pineal gland

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73
Q

What does the pineal gland secrete?

A

melatonin - triggers sleep

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74
Q

What photo pigment is associated with pineal gland/melatonin?

A

melanopsin

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75
Q

What is known as the branch point

A

the tecto-pulvinar system

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76
Q

What % of fibres from the optic nerve go to the tecto-pulvinar system

A

10%

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77
Q

What type of fibres from the optic nerve go to the tecto-pulvinar system?

A

all magno fibers

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78
Q

What is the superior colliculus?

A

known as the optic tectum in birds/reptiles

  • some visual processing, but very important in controlling eye movements
  • extra ocular eye muscles –> allows a person to see something without turning head
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79
Q

What are fixation cells

A

produce a lot of activity when keeping eyes very still

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80
Q

Build up cells

A

just before an eye moves –> a lot of activity

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81
Q

Burst cells

A

operate when actually making eye movement

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82
Q

What does must-modal mean?

A

integrates more than one sense

  • sensory modalities
  • e.g. vision and hearing –> visual orienting reflex
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83
Q

What two systems make up the branch point?

A

tecto-pulvinar system and geniculostriate system

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84
Q

What % of fibres from optic nerve go to the geniculostriate system ?

A

90%

- both magno and parvo

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85
Q

What is the geniculostriate system ?

A

basis of conscious perception

86
Q

What is the lateral geniculate nucleus (LGN)?

A

In the thalamus

executive secretary

  • involved in sorting info and relaying to the appropriate place
  • involved in controlling which info moves to striate (~40%)
87
Q

What is the paternal geniculate nucleus hooked up to

A

reticular activating system

  • when you become tired, thalamus begins blocking info
  • but can also allow more info in to get someone up and going (first thing in morning)
88
Q

Layers making up lateral geniculate nucleus

A

6 layers

  • 1 and 2 = magno
  • 3, 4, 5, 6 = parvo
  • reflect which eye the information comes from
89
Q

What does ipsilateral mean?

A

same side

90
Q

What does contralateral mean?

A

opposite side

91
Q

Which layers of the lateral geniculate nucleus are contralateral?

A

1,4,6

92
Q

Which layers of the lateral geniculate nucleus are ipsilateral?

A

2,3,5

93
Q

What is the primary visual cortex also referred to?

A

striate cortex or V1 or area 17

94
Q

What is the role of the striate cortex?

A

seat of conscious perception - allows us to report what we see
= feature analysis - linear orientation, colour, movement
- sends into to other parts of the brain

95
Q

What is cortical magnification and where does it take place?

A

striate cortes

  • fovea –> 0.01% of retina but 8% of striate
  • to get the same amount of detail as center image, letters in periphery need to be larger
  • visual cortex has a lot of cells devoted to the fovea –> higher detail
96
Q

What happens when there is damage to the striate?

A

Scotoma = blind pots
- areas someone cannot report on

Hemianopia = lost half of visual field (lacks half the image)

Little scotoma = loss of image in that area

Quadramtamopia = blind sight - see dissociation between conscious perception of what they can see and what they can do

  • some info still getting in
  • coming from different visual system
97
Q

What happens when the entire striatus is destroyed?

A

cortical blindness

98
Q

What cells did Hubel and Wiesel find?

A

simple, complex, hyper-complex/end-stop cells

99
Q

What are simple cells

A

respond to line orientation (in the visual cortex)

100
Q

What are complex cells

A

respond to a combination of line orientation and movement (e.g. diagonal line moving right)

101
Q

What are hyper-complex/end-stop cells

A

respond to stimuli of certain length, with certain line orientation, moving certain way

  • repsonds to different angles
  • responds to different line widths
102
Q

Describe the orientation column

A

organized in such a way that all cells responsible for an image are present (1mm) = all possible line orientations

103
Q

What is the ocular dominance column?

A

left and right eye have seamers slabs
- 80% respond to either eye (but better to one)
= hypercolumns

104
Q

Describe the Zeki addition

A

“The blobs and inter-blobs”

  • in hyper columns, blobs are colour sensitive (respond differently to various colours); areas between the blobs are not colour sensitive
105
Q

What is contrast?

A

the difference in brightness

106
Q

How is brightness quantified?

A

C = difference in brightness/sum of brightness

107
Q

Different types of grating include?

A

square wave = abrupt changes in brightness

sine wave = gradual changes in brightness (fading)

108
Q

What is spatial frequency?

A

number of lines within a given area

  • 2 thick lines = low spatial frequency
  • 6 thin lines = high spatial frequency
109
Q

What does high resolution mean?

A

high spatial frequency

110
Q

How is spatial frequency measured?

A

cycles/degree visual angle

Cycle = bar and its background together
Degree of visual angle = using trig, space on back of eye that object covers
- rule of thumb = used to estimate spatial frequency

111
Q

Spatial frequency is the relationship between

A

visual angle and distance from object and brightness

112
Q

What is Fourier’s insight?

A

turning a difficult function into a sum of simple functions (e.g. sine wave)

  • different starting points, line orientations, spatial frequencies - decompose complicated image –> mathematical formula = courier’s analysis
  • broken down –> stored
113
Q

What is Fourier’s synthesis?

A

take all the sine waves – sum them together and turn them back into an image

114
Q

What happens when you squint your eyes?

A

getting rid of high spatial frequency info

- eyes are out of focus so you’re missing fine detail

115
Q

What are seen using high spatial frequencies on a person’s face?

A

pimples, warts, wrinkles (fine detail)

116
Q

Describe the contrast sensitivity function - method of adjustment

A

increase contrast until person sees lines
- contrast threshold = smallest different in brightness = difference/sum (u graph)

  • constrast sensitivity = 1/contrast threshold (n graph)

We are not equally sensitive to all spatial frequencies

117
Q

Factors affecting sensitivity to spatial frequencies

A

species, age, lighting conditions

118
Q

What are species effects in spatial frequency

A 
Some species (e.g. cats) see metamers 
- cats can't see high spatial frequencies as well as humans, but are better with low spatial frequencies
119
Q

What are metamers

A

two things that are physically different but look the same

120
Q

How do you test for metamers?

A

Reduce contrast util cat chooses either image equally

- would normally choose the image with the observable bars

121
Q

What is the affect of age on spatial frequency?

A

babies are less sensitive to high spatial frequencies

  • can be tested through preferential looking task
  • can’t see things like a persons eyes, nose, smile
  • born with little, pudgy cones vs. adult cones which are much more slender and developed

seniors are also less sensitive to high spatial frequency
- can’t see wrinkles

122
Q

What is the affect of lighting conditions on spatial frequency?

A

bright daylight –> excellent high spatial frequency vision

middle mesonic/twilight –> lose a lot of high spatial frequency vision

scotopic/night –> very poor high spatial frequency vision

123
Q

What spatial frequency level is emotion often associated with?

A

low

124
Q

What is the spacial frequency channel?

A

group of cells responsible for responding best to specific spatial frequencies

  • up to 5 populations of cells (very high –> very low)
  • evidence that they are separate
125
Q

What is a symptom seen in MS and what is it?

A

Uthoff’s symptom

  • temporarily lose spatial frequency channel –> cells stop working properly (when person is feeling very emotional or has been exercising)
  • E.g. can see low and high but not middle - persons head looks like an egg with hair
126
Q

What are adaptation studies

A

constrast sensitivity vs. spatial frequency graph

  • measure before adaption
  • adapt person to specific spatial frequency
  • measure function after adaptation = see difference in sensitivity
  • higher and lower but middle are fatigued so they lose sensitivity
127
Q

what is orientation?

A

direction of line

128
Q

What is spatial frequency>

A

how many contours in a given area

129
Q

What two pathways make up the branch point after the striate cortex?

A

Temporal pathway (ventral path) and the parietal pathway (dorsal path)

130
Q

What is the temporal pathway ?

A
  • involves Parvo cells (colour and fine detail)

- the “what” pathway - involved in identifying objects

131
Q

What are the two stops along the temporal pathway?

A

V4 and inferotemporal cortex

132
Q

What is the V4 stop?

A
  • a lot of the cells in this area respond to differences in colour (~60%)
133
Q

What is the result of damage to the V4 area?

A

Cerebral achromatopsia

- tupe of colour vision problem that causes someone to not be able to see any colour at all

134
Q

What is the inferotemporal cortex?

A

recognizes things by their shape

135
Q

What is the result of damage to the inferotemporal cortex?

A

Prosopagnosia
- can’t recognize faces (even their own)

Fusiform face area and parahippocampal area are involved

  • also have trouble telling the difference between other things in categories (e.g. cars, dogs)
136
Q

What make up the parietal pathway?

A

Involves the medial temporal cortex and parietal cortex

137
Q

What is the medial temporal cortex responsive to?

A

motion

138
Q

What is the result of damage to the medial temporal cortex?

A

cerebral akinetopsia

- lose ability to see motion

139
Q

What is the function of the parietal cortex?

A

important in attention

140
Q

What is the result of damage to the parietal cortex?

A

neglect (hemi-spatial)

  • right side damed to parietal cortex –> right side neglect
  • problem with paying attention to things –> can’t see food on left side of plate; put makeup only on one side of face; draw only half a picture
  • when pressed –> do have some knowledge (even though they seem unaware; e.g. burning house)

NOT blind to the info just don’t pay attention to it

141
Q

What is light

A

electromagnetic radiation

142
Q

What do wavelengths correspond to?

A

colour

- short = blue; long = red

143
Q

What are chromatic colours?

A

red, green, blue (from spectrum)

144
Q

what are achromatic colours?

A

grey, black, white

white = all different wavelength in equal amounts ( a lot of light)
grey = all wavelengths but not as much light
black = doesn't send much light at all (but equal from all wavelengths)
145
Q

What 3 aspects of light do we pay attention to?

A

hue, brightness and saturation

146
Q

What is hue?

A

most closely related to wavelength

147
Q

What is brightness?

A

related to amplitude (height of waves)

148
Q

What is contrast

A

purity of colour

Pure (unsaturated) = monochromatic = one wavelength
Desaturated = made up of a picture of wavelengths
- fastest way to desaturate –> add white (can also be done by adding grey, black)

149
Q

Explain Newton’s insight

A

what we see as white isn’t white at all but a combination of wavelengths

  • sunlight is made up of a bunch of components
  • can use a prism to breakdown these components

Perception of colour is an illusion

150
Q

Explain Young and Helmholtz’s trichromatic colour theory

A

We only have 3 different colour receptors (3 kinds of cones)

  • evidence = colour matching studies
  • someone with normal vision can successfully complete this

Look at relative activity of each colour receptor allows us to see the colour of things = distributed coding
- economizes the number of receptors we need

151
Q

What is additive colour mixture

A

adding more wavelengths

  • blue + red + green = white
  • red + green = yellow
152
Q

What is subtractive colour mixture?

A

every time you add a pigment –> reduce amount of light reflected back to eyes

153
Q

what molecules are involved in colour tv?

A

phosphors = colour dots (mixing light)

154
Q

Who discovered mixing light

A

Seurat Pointillism = optical light mixing

- points of paint causing eye to see colour (by activating different cones)

155
Q

What photo pigment is associated with red cones?

A

erythrolabe = red catching (long wavelength light)

156
Q

What photo pigment is associated with green cones?

A

chlorolabe = green catching (med wavelength light)

157
Q

What photo pigment is associated with blue cones?

A

cyanolabe = blue catching (short wavelength light)

158
Q

True or false - there are more green and red cones vs. blue?

A

true

159
Q

What is chromatic aberration?

A

has to do with the way light passes through lens

- causes blue light to be a bit out of focus (too much blue –> blurry image)

160
Q

What make up the fovea?

A

100% red and green cones

- important for focus and detail

161
Q

What are colour deficiencies?

A

problems making certain distinctions between colours

162
Q

What was Dalton’s problem?

A

Couldn’t see red

- wore a red suit and thought it was grey

163
Q

true or false - colour deficiencies are sex linked?

A

Yes - occur on x chromosome

- more likely in males

164
Q

What are dichromats?

A

can only make 2 of the 3 photochmeicals

  • unable to make certain colour distinctions
  • can be shown by colour matching experiments (can mix two colours –> arbitrary third)
165
Q

3 types of dichromats?

A

protanopes, deuteranopes, tritanopes

166
Q

Explain protanopes

A

can’t make photopigment for red cones (erythrolabe)

- can’t tell the difference between red and green

167
Q

What are unilateral dichromats?

A

normal vision in one eye, but not the other (chlorolabe)

- have a neutral grey point

168
Q

Explain deuteranopes

A

can’t make the photopigment for green cones

- can’t tell the difference between red and green

169
Q

Explain tritanopes

A

Can’t make the photopigment for blue cones (cyanolabe)

  • see things in variations between turquoise green/blue to red
  • through genetics
  • quite rare
170
Q

What test can be used to test for colour deficiency?

A

Ishihara colour plate

- include “catch trials”

171
Q

Explain monochromats

A

can’t see colour, they can just see brightness

172
Q

Describe the problem with rod monochromats?

A

person has no mechanism for colour vision

  • see black and white and shades of grey
  • just have rods
  • lack of colour vision is the least of their problems though:
  • they have a system designed for night vision –> daylight is extremely bright
  • no cones so they lack fine detail
173
Q

Describe the problem with cone monochromats?

A

Have rods but only 1 type of cone

  • not uncomfortable in daylight conditions and can get fine detail but their body lacks the recipe for all 3 photo-pigments
  • for example if they lack red cones –> can see red but can’t make the distinguishment between red and blue or red and green (because the whole system is comparative) = need several different types to form a pattern
  • they are only being told how much light is being absorbed but not what colour it actually is (only how many AP produced = brightness)
174
Q

What are anomalous trichromats?

A

Have recipe for one photo-pigment a little bit wrong
- can figure this out through colour matching experiment –> use 3 projectors to match arbitrary colour but when they make mixture it doesn’t match (but they don’t realize) = mix colours differently from other people

  • recipes for med. and long wavelength cones are a bit too similar = differences between green and red aren’t as apparent as usual and cause these problems
175
Q

Explain tetrachromats

A

“the leading edge of evolution”

  • colour vision is continuing to evolve
  • can make 4 types of cones (photo-pigments)
  • mostly occurs in women
  • lack research
  • quite rare
  • can make colour discriminations the most of us can’t
176
Q

What are some acquired colour deficiencies

A
  • Glaucoma = fluid pressure gets so high it crushes some of the cells
  • Diabetic retinopathy = dying cones
  • normal aging = associated with cell death (rods and cones die too)
  • alcoholism/neurotoxins
  • -> because there are fewer blue cones, they are more vulnerable to damage
  • vitamin B12 deficiency –> optic nerve damage BUT affects red cones first
177
Q

What 3 observations did Hering make?

A
  1. varieties of colour deficiencies that never occur
  2. colour after images
  3. colour contrast: how to make colours look more vivid
178
Q

What colour deficiency never occurs?

A

Distinguishing between red and blue

  • green and red go together
  • yellow and blue go together

3 different cones but 2 opponent pairs

179
Q

Describe colour afterimages

A

yellow –> blue and blue –> yellow

green –> red and red –> green

180
Q

Describe colour contrast and how to make colours look more vivid

A

Certain colour combinations pop:

  • to make yellow look especially bright, put it beside blue (and vice versa)
  • to make red look especially bright, put it beside green (and vice versa)
181
Q

Hearing’s original theory?

A

When you see red –> build up of material in retina but when you see green it eats that material up (same with yellow and blue an black and white) - right about the pairings but not about how it worked

182
Q

Is red activating or inhibiting?

A

activating

- more AP = increase activation = faster than spontaneous activity

183
Q

Is green inhibiting or activating?

A

inhibiting

- more AP = increase inhibition = slower than spontaneous activity

184
Q

Explain simple colour opponent cells in visual system

A

opponent cell: red (+) on the inside and green on the outside (-)
- found in ganglion cells

185
Q

Describe double opponent cells in striate cortex

A

green (+)/red (-) on outside, green (-)/red (+) on inside = why we have such vivid colour vision

186
Q

In double opponent cells what produces maximum AP/second?

A

red in the center and green on the outside

187
Q

in double opponent cells what produces the lowest number of AP/second?

A

red on the outside and green on the inside

188
Q

What is colour constancy?

A

can still see colour accurately despite under different light conditions (wavelengths vary)

189
Q

What is emission spectra?

A

light emission from different wavelengths for various types of light

190
Q

What is depth perception?

A

has to do with how far something is in front of you (3rd dimension)
- we have a 2D image projected on retina but must find out about a 3 dimensional world

191
Q

Explain proximal cues

A

Visual angle is an ambiguous stimulus = dimensional ambiguity

192
Q

What is dimensional ambiguity

A

tells us about 2 different things

  • the actual size of object (very large = fills a lot of the visual field)
  • how far away in depth (close = fills a lot of the visual field)
193
Q

Explain the constructive approach

A

R. Gregory thinks of perception as problem solving/reasoning

  • take certain cues/clues and put them all together and figure how far object is
  • a number of depth cues only work in certain situations
194
Q

Explain ecological approach

A

AKA direct perception - J.J. Gibson

  • perception isn’t like reasoning, there is no figuring things out, there is no need to represent different aspects
  • we are like tuning forks = pick up relevant information/right evidence
195
Q

What are invariants?

A

things that don’t change based on perspective

196
Q

Cues of depth include?

A

physiological, pictorial and motion based cues

197
Q

What are the physiological cues?

A

from the lens (ciliary muscles/lens) and convergence of eyes (extra-ocular muscles)

198
Q

Explain cues from the lens

A

Accommodation - what the lens does in order to bring objects into focus
- only works from certain range = 20cm-3m

199
Q

Explain convergence of eyes

A

Drawing eyes inward to look at an object close by

- works better for close objects (

200
Q

What are the pictorial/monocular cues?

A
  1. relative/familiar size
  2. overlap/occlusion/interposition
  3. height in the field of view
  4. shading
  5. linear perspective
  6. atmospheric perspective
  7. texture gradients
201
Q

Explain relative/familiar size

A

know the actual size –> can see changing visual angle –> must be getting further away

202
Q

Explain overlap/occlusion/interposition

A

image covered must be further away

203
Q

Explain height in the field of few

A

objects close to horizon line seem further away

- objects below horizon seem closer; above horizon seem further

204
Q

Explain shading

A

shaded = further away

  • making assumption of where light source is from
  • gives 3D appearance
205
Q

Explain linear perspective

A

parallel lines appear to converge with distance

206
Q

Explain atmospheric perspective

A

things further away get blurrier - particles in the air scatter light
- useful when things are at quite a distance (>30 m)

207
Q

What illusions does atmospheric perspective give?

A
  1. snow or misty conditions –> make objects appear further than they actually are
  2. smoggy region –>objects appear closer than they actually are
208
Q

Explain texture gradients

A

With increasing distance, texture becomes more dense = smaller and closer together

  • combination of linear perspective, relative size and horizon line
  • works at a variety of distances
209
Q

What are the 3 motion-based cues?

A

relative motion/motion parallax, accretion and deletion, motion in depth

210
Q

Explain relative motion/motion parallax

A

object is closer –> moves in opposite direction quickly

object is far –> moves in same direction, slowly

211
Q

Explain accretion/deletion

A

Things get smaller and then larger as something covers them

212
Q

Explain motion in depth

A

object grows in visual field as it gets closer

  • baseball coming towards head
  • available very early in life

PSYC 2390 Midterm 1 (3 decks)

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