Central Visual Processing I Lec12 Flashcards

1
Q

The retina ganglion cells have 3 pathways:

A

magno, parvo, k pathway

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2
Q

Visual fields are ___ and ___ in the retina.

A

flipped and inverted

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3
Q

in the optic chiasm, ___ axons cross

A

nasal axons (temporal visual field)

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4
Q

nasal axons carry information from the

A

temporal visual field

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5
Q

in the optic chiasm ___ axons stay ipsilateral

A

temporal

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6
Q

LGN has 6 layers

the 2 magnolayers are ___

A

ventral

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7
Q

LGN has 6 layers

the 4 parvo layers are ___

A

dorsal

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8
Q

in the lgn, the inputs are segregated by

A

eye

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9
Q

lgn gets feedback input from

A

V1’s layer 6

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10
Q

V1 is ordered ____

A

retinotopically

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11
Q

in v1, more cortical area is given to

A

central vision/fovea

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12
Q

order of M,P,K in V1

A

M, P, and K pathways mix substantially here

M pathway is still partially seperated to provide a fast motion processing

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13
Q

All V1 neurons have retinotopy which is a ___ field position

A

receptive

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14
Q

V1 neurons are that orientation tuned

A

interblobs

look at angle of a light bar –> edges

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15
Q

V1 neurons that are center/surround

A

blobs

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16
Q

The V1 functional unit is a ____

A

hypercolumn

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17
Q

Ocular dominance hypercolumn =___ and ___ columns

A

right eye column + left
eye column

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18
Q

A complete hypercolumn =

A

ocular dominance hypercolumn
+ orientation hypercolumn + color blobs

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19
Q

One hypercolumn contains all the cortical machinery to fully analyze one point in visual space for all ___ and ___

A

orientations and both eyes

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20
Q

Input from optic radiations goes to___ in V1

A

layer 4

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21
Q

Output of V1 going to V2 leaves from ___

A

layers 2&3

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22
Q

Output from V1 to superior colliculus leaves from

A

layer 5

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23
Q

Feedback from V1 back to LGN leaves from

A

layer 6

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24
Q

___ has large (1.5mm) stripes that stain with cytochrome oxidase

A

V2

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25
Q

Dorsal pathway to ____ visual cortex

A

parietal

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26
Q

Ventral pathway to ___ visual cortex

A

temporal

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27
Q

the where pathway is the

A

dorsal pathway

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28
Q

the what pathway is the

A

ventral pathway

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29
Q

the where pathway is involved with

A

motion and
object localization

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30
Q

the what/ventral pathway si involved with

A

pattern and object recognition.

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31
Q

As you go to higher cortical areas… ___ integrate, summate, and enlarge

A

Receptive fields

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32
Q

lesions in higher cortical areas (above v1) usually manifest as specific visual deficits like

A

loss of color vision or form vision

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33
Q

lesions in V1 manifest as__ or ___

A

blindness or scotomas

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34
Q

ganglion cells in the retinal detect what (4)

A

spatial representation (receptive fields & retinotopy)
• retinotopy - the mapping from the retina to initial neurons
- luminence / intensity (esp. rods)
- spectral absorption (cones, color)
- spatial contrast (center/surround, ON/OFF,
edges)

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35
Q

spatial contrast is related to

A

center surround receptive fields

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36
Q

output from the retinal ganglion

A
  1. lgn
  2. superior colliculus
  3. hypothalamus
  4. pretectum
37
Q

what is another name for the retinogenciulate pathway

A

the visual processing pathway

38
Q

the superior part of the viosual field lands on the ___ part of the retina

A

inferior

39
Q

right superior field projects on to the ___ of the retina

A

bottom left of the retina

40
Q

first neurons that get binocular input are in the ___

A

striate cortex, not the lgn

41
Q

the left visual field gets represented in the ___ hemisphere

A

right

42
Q

X optic nerve —>

A

complete scotoma

43
Q

X optic chiasm:

A

bitemporal hemiopia.

44
Q

X optic tract on the right

A

lose left visual field

45
Q

lesion of optic radiations

A

Quadrantanopia

46
Q

leison of occipital cortex typically causes ___ hemianopias

A

macular sparing

47
Q

If Meyer’s loop (temporal pathway) is lesioned, the Quadrantanopia is ____ superior

A
48
Q

if Baum’s loop (parietal pathway) is lesioned in the optic radiations, the Quadrantanopia is ___

A

inferior

49
Q

lgn cells are binocular or monocular?

A

monocular.. they have functional segregation

50
Q

the __ pathway is very important for motion

A

M

51
Q

the __ pathway is involved with visual acuity & color

A

P

52
Q

the ___ pathway is involved with temporal resolution and luminance contrast

A

m

53
Q

Common properties of receptive fields in the retina and LGN (3)

A

center surround organization

mix of cells with on/off center

retinotopically ordered

54
Q

what may be color opponent (red/green or blue/yellow)

A

retinal ganglion or LGN

55
Q

within the ocular dominance columns are the ___ columns

A

orientation

56
Q

an on cell you get AP when light is shown in the

A

center

57
Q

each visual ___ neuron has a receptive field which is part of a retinotopic representation
and has receptive field proepries such as ocular dominance, orientation, and perhaps
other properties

A

cortical

58
Q

with ___ you dont see red without analyzing green as well

A

color opponency

59
Q

type II color opponentn cell is depolarized with __ and hyperpolarized with ___.

A

red and green

60
Q

doube opponent receptive fields encode both __ and ___ contrast

A

spatial and chromatic

e.g. in center red is on, green off

in surround red is off and green is on

61
Q

type ___ cells have spatial opponency and a weak color bias

A

type 1

62
Q

___ can be type 1, type 2, or double opponent

A

blobs

63
Q

are blobs monocular or binocular?

A

monocular

64
Q

what is “oriented in V2?”

A

thick disaprity and pale

65
Q

bilateral X of the ___ leads to a behavioral deficit ina task that requires the discirimination of objects

A

temporal lobe

66
Q

bilateral X of the ___ leads to a behavioral deficit ina task that requires the discrimination of locations

A

parietal

67
Q

The Magno system is specialized for high ___ and ___

A

temporal resolution (speed) and higher contrast gain,

68
Q

The K pathway is probably also specialized for ___ perception.

A

color

69
Q

what has center surround reeptor fields?

A

LGN and the retina

70
Q

Within __, the M, P and K pathways intermix substantially

A

V1

71
Q

V1 is highly __, with more cortex devoted to central vision.

A

retinotopic

72
Q

The anatomical structure of V1 is a 2mm thick sheet of cells, with__ layers

A

6

73
Q

If you record from a V1 neuron, if may have ___ domiannce or be ___

A

ocular domiannce or be binocular

74
Q

instad of center surround receptive fields, cells of v1 have ___ receptive fields

A

oriented

75
Q

Orientation tuning refers to the preference of a cell to be stimulated by an ___ of light presented at a particular angle

A

edge

76
Q

There are some V1 neurons that are not orientation tuned, but have center- surround receptive fields and are___

A

color-opponent

77
Q

The ocular dominance (OD) columns alternate between

A

left and right eye

78
Q

Neighboring columns of oriented cells in v1 usually have similar but slightly different ___ tuning

A

orientation

79
Q

So in general V1 neurons have, simultaneously,

A
  1. a receptive field position (reitnopathy)
  2. an ocular domiannce
  3. preferred orientation
80
Q

The segregation between the color blob
cells and the regular, oriented V1 cells found in the “interblobs” is the beginnings of the segregation between the “___ and ___

A

form” vision and color vision pathways,

81
Q

collection of orientation columns that would cover all the possible orientations, from horizontal through vertical and back, for a

A

given point in visual space.

82
Q

The orientation column map and the ocular dominance column bands are interwoven in V1 and run

A

at right angles to eachother

83
Q

There are two major visual processing streams after V2: the___ and ___ pathway

A

dorsal pathway and the ventral pathway.

84
Q

V1: blobs -> ____ stripes in V2

A

thin

85
Q

V1 interblobs -> ___ (inter) stripes in v2

A

pale

86
Q

layer 4B in V1 -> ___ stripes in V2

A

thick

87
Q

what is retinotopically organized?

A

v2 and v1

88
Q

The V2 pale stripes contain oriented cells, often end-stopped and probably involved in the detection of

A

curvature.

89
Q

The V2 thick stripes contain oriented, disparity cells and are probably involved in

A

stereo depth vision.