Central Visual Processing I Lec12 Flashcards
1
Q
The retina ganglion cells have 3 pathways:
A
magno, parvo, k pathway
2
Q
Visual fields are ___ and ___ in the retina.
A
flipped and inverted
3
Q
in the optic chiasm, ___ axons cross
A
nasal axons (temporal visual field)
4
Q
nasal axons carry information from the
A
temporal visual field
5
Q
in the optic chiasm ___ axons stay ipsilateral
A
temporal
6
Q
LGN has 6 layers
the 2 magnolayers are ___
A
ventral
7
Q
LGN has 6 layers
the 4 parvo layers are ___
A
dorsal
8
Q
in the lgn, the inputs are segregated by
A
eye
9
Q
lgn gets feedback input from
A
V1’s layer 6
10
Q
V1 is ordered ____
A
retinotopically
11
Q
in v1, more cortical area is given to
A
central vision/fovea
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
13
Q
All V1 neurons have retinotopy which is a ___ field position
A
receptive
14
Q
V1 neurons are that orientation tuned
A
interblobs
look at angle of a light bar –> edges
15
Q
V1 neurons that are center/surround
A
blobs
16
Q
The V1 functional unit is a ____
A
hypercolumn
17
Q
Ocular dominance hypercolumn =___ and ___ columns
A
right eye column + left
eye column
18
Q
A complete hypercolumn =
A
ocular dominance hypercolumn
+ orientation hypercolumn + color blobs
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
20
Q
Input from optic radiations goes to___ in V1
A
layer 4
21
Q
Output of V1 going to V2 leaves from ___
A
layers 2&3
22
Q
Output from V1 to superior colliculus leaves from
A
layer 5
23
Q
Feedback from V1 back to LGN leaves from
A
layer 6
24
Q
___ has large (1.5mm) stripes that stain with cytochrome oxidase
A
V2
25
Dorsal pathway to ____ visual cortex
parietal
26
Ventral pathway to ___ visual cortex
temporal
27
the where pathway is the
dorsal pathway
28
the what pathway is the
ventral pathway
29
the where pathway is involved with
motion and
object localization
30
the what/ventral pathway si involved with
pattern and object recognition.
31
As you go to higher cortical areas... \_\_\_ integrate, summate, and enlarge
Receptive fields
32
lesions in higher cortical areas (above v1) usually manifest as specific visual deficits like
loss of color vision or form vision
33
lesions in V1 manifest as\_\_ or \_\_\_
blindness or scotomas
34
ganglion cells in the retinal detect what (4)
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)
35
spatial contrast is related to
center surround receptive fields
36
output from the retinal ganglion
1. lgn
2. superior colliculus
3. hypothalamus
4. pretectum
37
what is another name for the retinogenciulate pathway
the visual processing pathway
38
the superior part of the viosual field lands on the ___ part of the retina
inferior
39
right superior field projects on to the ___ of the retina
bottom left of the retina
40
first neurons that get binocular input are in the \_\_\_
striate cortex, not the lgn
41
the left visual field gets represented in the ___ hemisphere
right
42
X optic nerve ---\>
complete scotoma
43
X optic chiasm:
bitemporal hemiopia.
44
X optic tract on the right
lose left visual field
45
lesion of optic radiations
Quadrantanopia
46
leison of occipital cortex typically causes ___ hemianopias
macular sparing
47
If Meyer's loop (temporal pathway) is lesioned, the Quadrantanopia is ____ superior
48
if Baum's loop (parietal pathway) is lesioned in the optic radiations, the Quadrantanopia is \_\_\_
inferior
49
lgn cells are binocular or monocular?
monocular.. they have functional segregation
50
the __ pathway is very important for motion
M
51
the __ pathway is involved with **visual acuity & color**
P
52
the ___ pathway is involved with **temporal resolution and luminance contrast**
m
53
Common properties of receptive fields in the **retina and LGN (3)**
center surround organization
mix of cells with on/off center
retinotopically ordered
54
what may be color opponent (red/green or blue/yellow)
retinal ganglion or LGN
55
within the ocular dominance columns are the ___ columns
orientation
56
an on cell you get AP when light is shown in the
center
57
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
cortical
58
with ___ you dont see red without analyzing green as well
color opponency
59
type II color opponentn cell is depolarized with __ and hyperpolarized with \_\_\_.
red and green
60
doube opponent receptive fields encode both __ and ___ contrast
spatial and chromatic
e.g. in center red is on, green off
in surround red is off and green is on
61
type ___ cells have spatial opponency and a weak color bias
type 1
62
\_\_\_ can be type 1, type 2, or double opponent
blobs
63
are blobs monocular or binocular?
monocular
64
what is "oriented in V2?"
thick disaprity and pale
65
bilateral X of the ___ leads to a behavioral deficit ina task that requires the ***_discirimination of objects_***
temporal lobe
66
bilateral X of the ___ leads to a behavioral deficit ina task that requires the discrimination of locations
parietal
67
The Magno system is specialized for high ___ and \_\_\_
temporal resolution (speed) and higher contrast gain,
68
The K pathway is probably also specialized for ___ perception.
color
69
what has center surround reeptor fields?
LGN and the retina
70
Within \_\_, the M, P and K pathways intermix substantially
V1
71
V1 is highly \_\_, with more cortex devoted to central vision.
retinotopic
72
The anatomical structure of V1 is a 2mm thick sheet of cells, with\_\_ layers
6
73
If you record from a V1 neuron, if may have ___ domiannce or be \_\_\_
ocular domiannce or be binocular
74
instad of center surround receptive fields, cells of v1 have ___ receptive fields
oriented
75
Orientation tuning refers to the preference of a cell to be stimulated by an ___ of light presented at a particular angle
edge
76
There are some V1 neurons that are not orientation tuned, but have center- surround receptive fields and are\_\_\_
color-opponent
77
The ocular dominance (OD) columns alternate between
left and right eye
78
Neighboring columns of oriented cells in v1 usually have similar but slightly different ___ tuning
orientation
79
So in general V1 neurons have, simultaneously,
1. a receptive field position (reitnopathy)
2. an ocular domiannce
3. preferred orientation
80
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 \_\_\_
form” vision and color vision pathways,
81
collection of orientation columns that would cover all the possible orientations, from horizontal through vertical and back, for a
given point in visual space.
82
The orientation column map and the ocular dominance column bands are interwoven in V1 and run
at right angles to eachother
83
There are two major visual processing streams after V2: the\_\_\_ and ___ pathway
dorsal pathway and the ventral pathway.
84
V1: blobs -\> ____ stripes in V2
thin
85
V1 interblobs -\> ___ (inter) stripes in v2
pale
86
layer 4B in V1 -\> ___ stripes in V2
thick
87
what is retinotopically organized?
v2 and v1
88
The V2 pale stripes contain oriented cells, often end-stopped and probably involved in the detection of
curvature.
89
The V2 thick stripes contain oriented, disparity cells and are probably involved in
stereo depth vision.
