Perception Flashcards

1
Q

What is a receptive field

A

Response in a visual neurons to a stimulus that is presented in a specific region of space

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2
Q

What is a retinotopic map

A

A visualisation that shows neural activity in response to visual cues

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3
Q

Do next door parts of the visual cortex respond to stimulus in next door bits of visual space

A

Yes

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4
Q

What is the optic nerve made up of

A

Axons of the ganglion cells

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5
Q

Where do medial axons intersect in the optic nerve

A

Optic ciasm

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6
Q

Do medial (nasal) neurons cross at the optic chiasm

A

Yes

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7
Q

Do temporal (lateral) neurons cross at the optic chiasm

A

No

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8
Q

What region of the visual cortex is sensitive to colour

A

V4

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9
Q

Do different regions of the visual cortex have different retinotopic maps

A

Yes

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10
Q

Do full retinotopic maps contain a representation of an entire contralateral hemifield

A

Yes

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11
Q

Where is V1 located

A

Calcarine sulcus

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12
Q

What stimulus is V4 sensistive to?

A

Colour

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13
Q

Is conscious perception linked to lower or higher areas of activity

A

Higher

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14
Q

Do early sensory regions “see through” illusions

A

Yes

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15
Q

In secondary areas, how can perception be elicited

A
  • Visual stimulus

- Direct electrical stimulation of the cortex

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16
Q

What is achromatopsia

A

Inability to perceive colour

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17
Q

Do lesions to V4 lead to deficits in shape perception

A

Yes

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18
Q

What is akinetopsia

A

An impairment in the ability to perceive motion

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19
Q

Damage to what region leads to akinetopsia

A

V5

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20
Q

Does disruption at V1 cause problems sooner than disruption at V5

A

No! There is a direct connection between the optic nerve and V5

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21
Q

What damage is more significant to V5: unilateral or bilateral

A

Bilateral

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22
Q

What region is responsible for motion

A

V5(MT)

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23
Q

What region is responsible for vision

A

V1

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24
Q

What region is responsible for processing whole objects

A

V3

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25
Q

Does V4 process complex shapes as well as colour

A

Yes

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26
Q

What is object constancy

A

Ability to recognise objects in different context despite variation in physical stimulus

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27
Q

What is the “What” stream of visual perception

A

The ventral (occipitotemporal) stream

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28
Q

What is the “Where” stream of visual perception

A

The dorsal (occipitoparietal) stream

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29
Q

What pathway does the ventral stream take

A

From the occipital striate cortex to the temporal lobe

30
Q

What pathway does the dorsal stream take

A

From the occipital striate crotex to the parietal lobe

31
Q

What is another name for the ventral stream

A

The inferior longitudinal fasciculus

32
Q

What is another name for the dorsal stream

A

The superior longitudinal fasciculus

33
Q

What is the main difference between the ventral and dorsal streams

A

The dorsal focuses on things, while the ventral is peripheral

34
Q

What area do dorsal neurons receptive fields focus encompass

A

The fovea (centre region)

35
Q

What is the breakup of ventral neurons

A

40% fovea, 60% elsewhere

36
Q

Does the ventral stream get more detailed the further along you go

A

Yes

37
Q

What stream is more important for guiding interaction with objects

A

The dorsal stream

38
Q

What problems might patients with lesions in the ventral stream face

A

They may be unable to identify objects but use the visual info to guide movement (telephone/clock case study)

39
Q

What problems might patients with optic ataxia (lesions to the parietal cortex) face

A

They may be able to identify objects but cannot use visual info to guide action

40
Q

What is a delayed matching to sample experiment

A

Monkeys must pick out one object out of two to get a reward thereby engaging the ventral “what” stream

41
Q

What is a land mark discrimination problem

A

Monkeys must choose a location to get a reward thereby engaging the dorsal “where” stream

42
Q

Do unilateral lesions produce apparent deficits in the dorsal or ventral streams

A

No.

43
Q

Do bilateral lesions produce apparent deficits in the dorsal or ventral streams

A

Yes

44
Q

Is there cross-talk across hemispheres via the corpus callosum in the dorsal and ventral streams

A

Yes

45
Q

What is the primary area of the brain for processing objects

A

The Lateral occipital complex

46
Q

How was the lateral occipital complex discovered

A

PET that controlled for scrambled objects and familiar objects

47
Q

Do visual processing areas have connection to memory areas

A

Yes

48
Q

What is the repetition suppression effect

A

Lower BOLD response in second presentation.

49
Q

What does the repetition suppression effect represent

A

Perhaps increased neural efficiency

50
Q

Is the lateral occipital complex sensitive to texture or shape changes in infants

A

Shape

51
Q

What is a gnostic unit

A

A neuron that recognises a complex object (the grandmother cell)

52
Q

What is the hierarchical coding hyptohesis

A

Perception of elementary features is combined to create an object that can be recognised by gnostic units

53
Q

What is the ensemble coding hypotheseis

A

Objects are defined by simultaneous activation of a set of defining properties

54
Q

What is top-down facilitation

A

Orbitofrontal cortex predicts an object from partial visual input then it goes to the ventral stream for object recognition

55
Q

What is decoding

A

Looking at brain activity and predicting stimulus

56
Q

What is specificity

A

Certain brain areas are responsible for facial recognition

57
Q

What brain areas are responsible for movement information about the face such as direction of gaze and emotive expression

A

The right STS

58
Q

What brain areas are responsible for invariant features such as eye spacing

A

Ventral face pathway

59
Q

What brain areas are responsible for the face

A

Fusiform face area

60
Q

What area is responsible for scenes

A

Parahippocampal place area

61
Q

What areas are responsible for bodies

A

Extrastriate body area and fusiform body area

62
Q

What is view invariance

A

The ability to differentiate beween ambiguous cirucmstances - see things from any angle

63
Q

What is recognition by components?

A

The ability to infer from features (geons) basic 3D objects

64
Q

What is apperceptive visual agnosia

A

Cant put the whole together but can do basic components

65
Q

Lesions to what area lead to apperceptive visual agnosia

A

Ventral right posterior

66
Q

What is integrative visual agnosia

A

Can perceive parts but not the whole. Difficulty with overlap

67
Q

What is associative visual agnosia

A

Can perceive objects with visual system but can’t give them meaning. There is no coneptual knowledge

68
Q

Lesions to what area lead to associative visual agnosia

A

Left posterior

69
Q

What is the sensory/functional hypothesis

A

Conceptual knowledge comes from the sensory input and motor input (for objects)
- these dependent on the relevant neural regions

70
Q

What is the domain sepcific hypothesis

A

Conceptual knowledge organisaed by evolutionary categories

71
Q

What is prosopagnosia

A

The inability to recognise faces

72
Q

How does prosopagnosia usually occur

A

Bilateral lesions in the ventral pathway especially the occipital and FFA