Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PSYC 102 - sensory > Midterm 2 > Flashcards

Midterm 2 Flashcards

1
Q

name of the two visual streams

A

ventral - temporal
dorsal - parietal
for vision and interaction in the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how many ganglion cell types are there and what are their names

A

M ganglion

P ganglion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

M ganglion cells

A

Magnocellular layers in LGN (layers 1 and 2 - inside)
fucntion movement and low light vision
high conversion of rods goes through M ganglion cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

P ganglion cells

A 
Parvocellular layers in LGN (3, 4, 5 & 6 - outside)
function colour, texture and depth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

classic visual pathway in the brain

A

M ganglion - magno LGN - V1 –dorsal— paritel lobe

P ganglion - parvo LGN - V1 —-ventral— temporal lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how lesion / ablation studies work

A

animal trained to indicate perceptual ability
specific part of brain is ablated or removed
animal is retrained to determine which perceptual abilities remain
results reveal which portions of the brain are responsible for specific behaviours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

classic ablation study for what and where pathways

-set up

A

animals trained on object discrimination task
-monkey shown an object
-then present with two choice task
-reward given for detecting target object
also trained on spaticial landmark discrimination problem
-monkey is trained to pick the food well next to a cylinder - so there is a spatital relationship and no object discrimination
then temporal and parietal lesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

classic ablation study

results

A

temporal lobe removed = problems in object discrimination task so what pathway
parietal lobe removed = problems in landmark discrimination task so where pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

behaviour of patient DF and conclusions

A

damage to ventral pathway die to carbon monoxide posioning
could not tell orientation (perceptual orientation matching) of the slot but could actively post a letter into it (visuomotor posting)
ventral stream = what
dorsal stream = how
really prfound deficit - brain knows what it is at some level but cnanot do it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how did what where evolve

A

what and how

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the inverse projection problem

A

an image on the retina can be caused by an infinite number of objects
fundamentally ambigious at the level of the retinal image - need to impose additional constraints
so no specific right way object recognition must work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what else makes object recognition tricky

A

huge variation - eg loads of pictures of dolphins, lots of inconsistencies but our brain still knows is a dolphin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does gestalt mean

A

german word

configuration or pattern

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

according to gestalt perception…

A

is not built up from sensations but is a result of your brain imposing perceptual organization on incoming stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

gestalt principles are known as..

A

heuristics = best guess rules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

6 gestalt organizing principles

A 
good continuation 
proximity / similarity
common fate
common region
uniform connetedness
meaning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

good continuation

A

continuous shapes viewed as single segmented obejcts

helps us perceive a pile of rope as one continous object and not all broken up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

proximity / similarity

A

things that are bear to each other are grouped together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

common fate

A

things moving in the same direction are grouped together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

common region

A

elements in the same region tend to be grouped closer together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

uniform connectedness

A

connected a region of visual properties are peceived as a single unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

meaning

A

interpret images in line with top-down knowledge

eg we see faces everywhere and in everything. us imposing top down knowledge on inanimate stuff

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

explain gestalt laws competring

A

leads to an ambigous percept
shows there isn’t a correct way to process images
brain just tries to apply the heuristics to disambiguate the info

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

charlie chaplin mask illusion

A

we have a lifetime experience seeing faces
never see them as concave - always projecting out
so we impose structure on the world
and so see both sides of the mask as pointing out
cannot see otherway round
top down imposition of knowledge by the brain on the bottom down world

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Biederman recognition by components theory

A

simple computational model of object recognition
36 geons
each geon is uniquely identifiable from most viewpoints
objects can be identified if geons can be identified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

evidence from Biederman

A

objects harder to recognise if geons are obscured, easy to recognise if can see geons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

strengths of biederman

A

viewpoint invariance

represents 3D structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

weaknesses of biederman

A

complexity of representation
doesn’t easily represent subtle metric differences (ie distance between the eyes)
recognition is at the level of categories (chair vs table) rather than individuals (my chair vs office chair), also trump vs someone dressed up as trump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

modern day version of recognition by componenets

A

deep neural networks
modern machine vision
architecture for performing object recognition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

how deep neural networks work

A

series on interconnected layers of modelled neurons
node = neuron / pop of neuron
input
basic processing at ealry layers eg 100000000 instead of just geons, look a lot like primary visual cortex
as progress through the layers = more and more complex representations
even modern machine learning use same general basic approach
building blocks put together to descirbe objects in detail
note this is how AI works

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

meaningfulness or familiarity

A

things are more likely to form groups if the groups appear meaningful or similar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

meaningfulness or familiarity experiment

A

how may toothbrushes in the image
if you show the image to a neural netowrk straight up 2, if shown to a person = 1 as second huge one only seen on inspection as our brain uses prior knowledge to constrain inputs coming in from the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

neurons response in area IT

A

their responses are similar within each object accross viewpoints
so can recognise all dolphins
so respond to object irrespective of where it is in the visual field
population code and not a unit code
perceptual experience due to entrire distribution of activity is across the cortex and not one very loud neuron
converging inputs into IT
IT - inputs from whole bunch of areas, why neurons can be so selective in IT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

IT an new objects

A

we have to be able to rapidly learn new infor but can’t have brain reconfiguring everytime it sees something new. so need stability and flexibility
flexible microwire - implanted in brain and moves with the brain - will follow the same neuron in the brain for months and months at a time
stability - brain processes monkey face the same
despite stability responses are flexible during learning = plasticity
series of novel objects presented to mokey = cell goes all over the place. as animal learns this activity becomes sterotyped and constant
period of plasticity before stable response turns up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what do we mean by modules in the ventral pathway

A

specialised chunks of cortex perform somewhat different perceptual functions
based off single cell recording in monkies = specific cells for faces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Nancy Kanswisher study

A

fMRI

face areas on left and right hemispheres and 2 for outdoor scenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what brain area is for

faces

A

fusiform face area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what brain area is for

scenes/ landmarks

A

parahippocampal place area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what brain area is for

intact over scrambeled objects

A

lateral occipital complex

40
Q

are the FFA/PPA/LOC innate?

A

hard to answer but certainly develop early in life

41
Q

Tsao’s research on face patches

A

macaques in fMRI
localized face selective regions
lots of areas
then single cell recording in these areas
used scrambeled patterns as a base for 0
but only high decoding activity specifically for human faces over everything else in one area
pattern of activity is what matters
lots of areas process faces but only some are face specific but others firs for lots of objects, faces included

42
Q

what happens when motion perception fails

A

akinesthesia

43
Q

hubel and weisel discovery for motion perception -

A

direction selective cells in the cat V1

almost all neurons in area MT are also direction selective

44
Q

psychophysical evidence for motion detectors and why

A

motion after effect
provides evidence for direction and rotatioanlly selective neurons
exposure to moving stimuli causes the most responsive neurson to stop responding after a while
even when a stationary stimulu is presented these neurons aren’t as active and neurons that prefer the opposite direction are more active and they bias perception

45
Q

motion detectors

A

not simply a static visual field but temporal dimension
spatio-temporal receptive field
responds to a particular direction of motion (preferred direction) and not as much to other (null/anti-preffered) directions
only when stimulus MOVES in the receptive field

46
Q

explain the appeture problem

A

is the consequence of a limited receptive field in V1

so square moving diagonally right with a small appeture can look like vertical upwards movement

47
Q

how is the appeture problem solved

A

cells later in the visual system integrate information from the appeture of multiple complex cells
many downstream neurons in MT can do this
so the receptive field of MT neurons will encompass the movement of the whole square

48
Q

what experiments proposed the link between motion perception and MT

A

causation study
Newsome
correlated dot motion - degree of coherance manipulated
part 1 - determined a single neuron in MT can discriminate motion as well as the monkey. used left right choice and recorded activity of neurons that responded maximally to one direction, if neuron responded alot then experimenter guessed the motion was left, therwise right. accuracy of neuron computed by histogram
part 2 - ablated MT in monkeys - severe deficits following selective lesion of MT
part 3 - microstimulation
-mokey performed left vs right discrimination - pass trials of stimulating pulses into collumn of neurons that prefer left motoin = biased the monkeys to chose left even if 90% of dots moving right

49
Q

explain the monkey training stage of using correlated dot patterns

A

trained monkeys to do as well as humans
graph x axis = degree of correltaion in movement of dots
y axis = behavioural performance
wiggly curve up (slow, steep, slow)

50
Q

organization of MT

A

like ice cube tray model

51
Q

what is biological motion

A

another example of kinetic depth effect
light point walker
shows male vs female, body size, affect etc

52
Q

fMRI of bio motion

A

processed in the superior temporal sulcus STS (next to MT)
thought the STS bridges MT and IT - the two streams dorsal and ventral
this region is thought to be crticial for interpreting actions of others in social situations

53
Q

what is visual neglect

A

disorder in which individuals are unaware of events in the space opposite their lesion
-can just be vision but tends to include other sensory or mototr deficits
importantly not dues to a sensory system problem eg abnormal vision
neglect is generally regarded as a selective lack of attention

54
Q

two examples of visual neglect seen in class

A

house on fire = listen to go over lecture example
old lady shown bathroom picture only named items from one half of the image, did name object in the middle - they don’t always do this

55
Q

impact of visual neglect on a patient

A

live in a different world - won’t eat food from one side of their plate, ignore people etc
may neglect parts of their own body - makeup and not accept ownership of left limbs
may even physically abuse their left side

56
Q

visual neglect and the brain

A

occurs in 11-37% patients following brain damage
right inferior parietal lobe / superioral temporal gyrus = common areas
may includ other lesion sites
-left TPJ
-supramarginal or angular gyrus
-inferior and middle frontla gyri
also subcortical lesions to thalamus, basal ganglia and midbrain

57
Q

can you recover from neglect

A

yes, often after an acute injury

then left with extinction usually

58
Q

what is extinction

A

failure to detec a stimulus contralateral to a lesion during simultaneous bilateral stimulation (so stimuli presented on both sides at the same time, would get right if just presented one at a time)
= competition

59
Q

explain the mental imagery study

A

done in Milan with two locals
subject asked to imagine themselves in a popular plaza
recall the shops and buildings from the cathedral or the opposite side of the street
both patients only named shops on the right side
when asked to do it from the reverse perspective again only named right shops (just from this new perspective)
not sue to difficulty in recall obviously
but info cannot be accessed even when relying on mental imagery so its more than just don’t act on info, they don’t have the info in the first place

60
Q

what is simultagnosia / balints syndrome

A

complete inability to attend to more than one feature regardless of the side of presentation - even in the fovea
when presented with two spatially conjoint objects (eg pen crossing a pencil)
-will report only one
-may report the other in other trials but only one per trial

61
Q

brain area damage associated with simultagnosia

A

also known as balints

bilateral damage to the parietal lobes

62
Q

three types of cues for depth perception

A

oculomotor
monocular
binocular

63
Q

define oculomotor cues

A

cues based on sensing the position of the eye and luscle tension

64
Q

define monocular cues

A

cues that rely on only one eye

65
Q

define binocular cues

A

cues that rely on both eyes

66
Q

explain types of oculomotor cues

A

convergence - knowing the inward movement of the eyes when we focus on nearby objects
accomodation - feedback from changing the focus of the lens

67
Q

explain the 2 broad types of monocular cues

A

pictorial cues - sources of depth information that come from 2D images liek pictures
movement produced cues

68
Q

name 8 types of pictorial cues and explain when not obvious what they mean

A

oclusion - one object covers another
relative height - higher in visual field = more distant
relative size = if same size objects, closer one will take up more sapce on retina
familiar size - distance info based on knowledge of object size
perspective convergence - parallel line come together in the distance
atmospheric perspective - far away = blue tint
texture gradient = equal spcing appears more packed if further away
shadows

69
Q

explain the two types of motion-produced cues

A

motion parallax - close objects in direction of movment glide rapidly past but objects in the distance move slowly (truck on long road example)
deletion and accretion (occlusion in motion) - objects are covered or uncovered as we move relative to them

70
Q

what are vergence movements and explain the two tyes

A

eyes moving to keep the object of fixation on the fovea of both eyes
convergence = when an object gets closer
divergence = object gets farther

71
Q

what is binocular disparity

A

your eyes get two different images of the world

72
Q

what is a horopter

A

an imaginary circle that passes through the point of focus
objects on the horopter will have equal disparity in the two eyes
it is an imaginary line of zero disparity where point of light from a given object will fall in corresponding locations

73
Q

define disparity

A

the difference in where light is on the retina of the focus point and the image

74
Q

the closer the object to the eye relative to the point of fixation the …… (disparity)

A

bigger distance the closer to the retina

75
Q

what can binocular disparity tell us about

A

cue to depth

76
Q

crossed disparity is when

A

th object is infront of the fixation point

77
Q

uncrossed disparity is when

A

the object infront of you is behing the fixation point

78
Q

when inside the horoptor (but not infornt of you), objects in the near eye have…. than the far eye

A

less disparity

79
Q

when outside the horoptor (but not infornt of you), objects in the near eye have….. than the far eye

A

more disparity

80
Q

what is stereopsis

A

depth information provided by bioncular disparity cues

  • steroscope uses two pictures from slightly different vewpoints to give the impressionof depth and solidarity
  • 3D movies use this principle
81
Q

explain the physiology of depth perception

A

neurons have been found that respond best to depth perception
=bioncular depth cells or disparity selective cells
= response best to a specific degree of disparity between the images on the left and right retinas

82
Q

monkey experiment showing the physiology of depth perception

A

monkeys viewed textured gradients that were 2D picutres and 3D sterograms
recordings from a neuron in the parietal lobe showed
cells responded to pictorial cues
cell also responded to binocular disparity

83
Q

cat experiment on binocular disparity and depth perception

A

cats reared by alternating vision between two eyes (otherone covered by an eyepatch)
results showed they had
-few binocular neurons
-were unable to use binocular disparity to perceive depth
this happens in around 10% of adults = stereoblind. but it is ok as stereopsis isn’t helpful for distances beyond about 6ft anyway

84
Q

what is the visual angle

A

proportion of the visual field occupied by an object
think of eye christmas tree drawing with angle labelled
see slide40 lecture 9 if cannot remember

85
Q

how can we infer the size of an object

so if written in an equation…

A

relationship between the visual angles and distance
perceived size= retinal image size x perceived distance
P=RD

86
Q

what is emmert’s law

A

objects that generate retinal images of the same size will look different in physical size if they appear to be located at different distances

87
Q

what is an optic array

A

structure created by the surfaces, textures and contours in the environment

88
Q

what happens to the appearances of objects as the observer moves past them

A

optic flow

self-prodiced information

89
Q

what is the gradient of flow in optic flow

A

difference in flow as a function of distance from the observer

90
Q

what is focus of expansion in optice flow

A

th point in the distance where there is no flow
the focus of expansion is always centered wherever you are heading and provides invariant information that reain constant while the observer is moving

91
Q

circle explaining optic flow

A

movement creates flow which provides inromation for more movement = back to movement at the top of the circle again

92
Q

swinging room experiment

A

walls of a room moving = child will fall over

93
Q

name the three brain areas involved in movement, action and perception

A

premotor (mirror area(
posterior parietal
medial superior temporal area MST

94
Q

the physiology of navigation

studies to back up

A

optic flow neurons - neuron in the MST of mokeys respond to optic flow patterns
maybe go over end of lecture 9 for clarification of end exmaple

95
Q

what does affordances mean

A

made up of information of what an object is udes for

they indicate potential for action as part of our perception

96
Q

evidence for affordance of objects in humans

A

people with certain types of brain damage show that even though they may not be able to name objects, they can still describe how they are used ot can pick them up and use them

97
Q

evidence for affordance of objects in monkeys

A

PRR - parietal reach area
neurons in the posterior parietal cortex respond before monkeys grasp an object thus signal the intention to grasp
neurons from this region send signlas directly to the premotor area that are immediately anterior

PSYC 102 - sensory (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions