Reveiw Of Vision
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The visual and oculomotor systems Peter H. Schiller, year 2006
Review,
the visual and oculomotor systems
Basic wiring of the visual system
fix
Primates
left hemifield
right hemifield
Horopter (Vieth-Muller circle)
nasal
temporal
PARIETAL LOBE
LGN
NOT p
m
terminal nuclei
MT V
superior colliculi
4
V
3
V
2
V
1
e
TEMPORAL LOBE
er ph is
le ft he m
is ph er
e
m he ht rig
optic chiasm
FRONTAL LOBE
Retina and LGN
pigment epithelium
cones
rods
photoreceptors
OPL cone horizontal
H
ON
OFF
bipolars
ON
IPL AII ON
OFF
amacrine ganglion cells
incoming light
to CN CNS S
Visual cortex
Transforms in V1 Orientation
Direction
Spatial Frequency
Binocularity ON/OFF Convergence Midget/Parasol Convergence
Three models of columnar organisation in V1 Original Hubel-Wiesel "Ice-C
ube" Model
Cortical
Left Eye
Right Eye
Sub-cortical
m
Radical Model
1m
Midget Parasol
Left Eye
Right Eye
Swirl Model
Figure by MIT OCW.
Striate Cortex Output Cell
Intracortical
LEFT EYE INPUT
Midget ON Midget OFF
Midget ON Midget OFF
Parasol ON Parasol OFF
Parasol ON Parasol OFF
luminance color orientation spatial frequency depth motion
RIGHT EYE INPUT
The ON and OFF Channels
The receptive fields of three major classes of retinal ganglion cells
ON
OFF
ON/OFF
inhibition
inhibition
inhibition
Action potentials discharged by an ON and an OFF retinal ganglion cell Stimulation confined to receptive field center
ON cell
OFF cell Stimulation of the entire receptive field
ON cell OFF cell dark spot
light spot
light stimulation condition time
The midget and parasol channels
MIDGET SYSTEM
PARASOL SYSTEM
neuronal response profile
OFF
ON
time
ON
OFF
Projections of the midget and parasol systems Midget
V1
Mixed
V2
Parasol
w
LGN
P
?
M
MT
V4
Midget Parasol
PARIETAL LOBE
TEMPORAL LOBE
Spatial Frequency H
Processing Capacity
L H
L
Midget System Parasol System
Temporal Frequency H
L L
H
Figure by MIT OCW.
Color vision and adaptation
Basic facts and rules of color vision
1. There are three qualities of color: hue, brightness, saturation 2. There is a clear distinction between the physical and psychological attributes of color: wavelength vs. color, luminance vs. brightness.
3. Peak sensitivity of human photoreceptors (in nanometers): S = 420, M = 530, L = 560, Rods = 500 4. Grassman's laws: 1. Every color has a complimentary which when mixed propery yields gray. 2. Mixture of non-complimentary colors yields intermediates. 5. Abney's law: The luminance of a mixture of differently colored lights is equal to the sum of the luminances of the components. 6. Metamers: stimuli producing different distributions of light energy that yield the same color sensations.
Basic facts about light adaptation 1. Range of illumination is 10 log units. But reflected light yields only a 20 fold change (expressed as percent contrast). 2. The amount of light the pupil admits into the eye varies over a range of 16 to 1. Therefore the pupil makes only a limited contribution to adaptation. 3. Most of light adaptation takes place in the photoreceptors. 4. Any increase in the rate at which quanta are delivered to the eye results in a proportional decrease in the number of pigment molecules available to absorb those quanta . 5. Retinal ganglion cells are sensitive to local contrast differences, not absolute levels of illumination.
The color circle
white
white
Yellow
saturation
Green Red
Blue
black
hue
Response to Different Wavelength Compositions in LGN Blue ON cell Yellow ON cell 90
90
135
135
45
45
Spikes per Second
180
10 20 30 40 50 60
225
0
180
315
20 40 60 80 100
225
270
Red ON cell
90
90
135
135
45
10
225
20
30
315 270
315 270
Green OFF cell
180
0
40
0
180
45
10 20 30 40 50
225
maintained discharge rate
315 270
0
Depth perception
Cues used for coding depth in the brain
Oculomotor cues accommodation vergence
Visual cues Binocular stereopsis
Monocular motion parallax shading interposition size perspective
stereo camera
MOTION PARALLAX, the eye tracks
1
a
2 b
eye movement
a
object motion
1
The eye tracks the circle, which therefore remains stationary on the fovea Objects nearer than the one tracked move at greater velocities on the retinal surface than objects further; the further objects actually move in the opposite direction on the retina.
2
b
Form perception
Three general theories of form perception:
1. Form perception is accomplished by neurons that respond
selectively to line segmens of different orientations..
2. Form perception is accomplished by spatial mapping of
the visual scene onto visual cortex.
3. Form perception is accomplished by virtue of Fourier analysis.
Eye-movement control
superior colliculus
medial eye fields frontal eye fields parietal cortex
visual cortex MEF p
FEF
LIP
SC ce
sts
V1 ls
BS
V2
medial eye fields
frontal eye fields
parietal cortex
superior colliculus ablated
visual cortex MEF
Anterior system
p
FEF
LIP
SC ce
sts
V2 V1
ls BS
Posterior system
Summary of the effects of electrical stimulation:
FACILITATION
V1 & V2, upper V1 & V2, lower V4 LIP FEF
MEF
INTERFERENCE
FIX INCREASE
NO EFFECT
Summary of the effects of the GABA agonist
muscimol and the GABA antagonist bicuculline
Target selection muscimol
V1
INTERFERENCE
FEF
INTERFERENCE
LIP
SC
Visual discrimination muscimol
bicuculline INTERFERENCE
V1
bicuculline
DEFICIT
DEFICIT
FACILITATION
FEF
MILD DEFICIT
NO EFFECT
NO EFFECT
NO EFFECT
LIP
NO EFFECT
NO EFFECT
INTERFERENCE
FACILITATION
Hikosaka and Wurtz
Saccade to new location
A
1. 2. 3. 4.
1 B
V1, V2, V4, IT, LIP, etc.
A
what?
2
C
What are the objects in the scene? Which object to look at? Which object not to look at? Where are the objects in space?
5. When to initiate the saccade?
B
V1, V2, LIP, FEF, MEF
Br a
A
which?
3
C B
in a
V1, V2, LIP
re a
si nv olv ed
A
which not?
4
C B
V1, V2, FEF, SC
A
where?
5
C B A
LIP when?
C
Midget
V1
Auditory
V2
Mixed
?
?
Parasol
system
w
LGN
Somatosensory
P M
Midget Parasol
system
V4
MT Posterior system PARIETAL LOBE
?
TEMPORAL LOBE
Olfactory
system
w
SC
?
BG
rate code
BS
BS
FRONTAL LOBE FEF MEF
SN vector code
system
vector code place code
Vergence system
Accessory optic system
Smooth pursuit
Anterior system
Vestibular
system
Motion perception
Summary of cell types in V1
s1
s5
D
D L
.1 .2 .3 .4 .5 DEGREES OF VISUAL ANGLE
.1
.3
.2
.4
.5
.7 deg
.6
L D
s2 L
D
s6 .1 .2 .3 .4 .5 .6 .7 DEGREES OF VISUAL ANGLE
.1
s3
D
.8
.2
.3
.2
.3
.4
.5
.6
.7
.4
.5
.6
.7
.8
.9
.9
.1
.2
L
.3
.2
.4
L
s4
.1
1.1 deg
D L
L
1.0
deg
s7
D
.8
D
L
L .1
L
.5
.6
.7
D
.8
.9
1.0 deg
L
D .3
.4
.5
.6
deg
CX
D L
D
.1
.2
.3
.4
.5
.6
.7
.8
.9
1.0 1.1
1.2 deg
Figure by MIT OCW.
Major Pathways of the Accessory Optic System (AOS) Velocity response of AOS neurons = 0.1-1.0 deg/sec Number of AOS RGCs in rabbit = 7K out of 350K
2
Cortex 1
Cerebellum
Ant
3 climbing fibers Prime axes of retinal direction-selective neurons
NOT
Inferior Olive Semicircular canals
D 1
M 2,3
Vestibular Nucleus
L
rate code
BS
BS
2,3
Terminal Nuclei
vestibulo-ocular reflex
Effects of lesions on vision
Summary of lesion deficit magnitudes PLGN
MLGN
V4
MT
color vision
severe
none
mild
none
texture perception
severe
none
mild
none
BASIC VISUAL FUNCTIONS
VISUAL CAPACITY
pattern perception
fine
severe
none
mild
none
shape perception
fine
severe
none
mild
none
coarse
mild
none
none
none
brightness perception
none
none
none
none
coarse scotopic vision
none
none
none
none
fine
severe
none
mild
mild
coarse
mild
none
none
mild
fine
severe
none
none
none
coarse
pronounced
none
none
none
contrast sensitivity
INTERMEDIATE
stereopsis
motion perception
none
moderate
none
moderate
flicker perception
none
severe
none
pronounced
choice of "lesser" stimuli
severe severe
none
severe
none
visual learning
not tested
not tested
severe
none
object transformation
not tested
not tested
pronounced
not tested
Prosthetics
Figure by MIT OCW.
The size and location of the regions activated in the monkey V1 by the dotted circle presented in the visual field 90
5 4
135
90
5
45
4
135
45 3
3 2
2 1
1
180
0
225
180
0
315
225
315
270 2
3
4
270
270 270
1
3
2
1
2
3
4
270
270
1
315 225
315 225
0 180
0 180
45
90
4
45
135
90
90
135
90
4
3
2
1
The size and location of the regions activated in the monkey V1 by the dots presented in the visual field 90
256 points
5
135
135
45
4
90
55
45
4 3
3 2
2 1
1
180
0
225
180
0
225
315
315
270 2
3
4
270
270 270
1
3
2
1
2
3
4
270
270
1
315 225
315 225
0 180
0 180
45
90
4
45
135
90
90
135
90
4
3
2
1
Illusions
The Hermann grid illusion
The most widely cited theory purported to explain the illusion:
ON
larger response
ON
smaller response
Due to antagonistic center/surround organization, the activity of ON-center retinal ganglion cells whose receptive fields fall into the intersections of the grid produces a smaller response than those neurons whose receptive fields fall elsewhere.
Differently oriented vertical and horizontal lines reduce illusion
Retinal ganglion cell receptive field layout at an eccentricity of 5 degrees
At the eccentricity of 5 degrees the 0.5 by 0.5 degree visual angle area outlined impinges on 365 midget cells and 50 parasol cells. Half of these are ON and half OFF cells. The layout of the ON cells is shown in B and C.
5mm
5 deg of visual angle
Retinal midget cells
0.5 deg of visual angle
Retinal parasol cells
Review,
the visual and oculomotor systems
Basic wiring of the visual system
fix
Primates
left hemifield
right hemifield
Horopter (Vieth-Muller circle)
nasal
temporal
PARIETAL LOBE
LGN
NOT p
m
terminal nuclei
MT V
superior colliculi
4
V
3
V
2
V
1
e
TEMPORAL LOBE
er ph is
le ft he m
is ph er
e
m he ht rig
optic chiasm
FRONTAL LOBE
Retina and LGN
pigment epithelium
cones
rods
photoreceptors
OPL cone horizontal
H
ON
OFF
bipolars
ON
IPL AII ON
OFF
amacrine ganglion cells
incoming light
to CN CNS S
Visual cortex
Transforms in V1 Orientation
Direction
Spatial Frequency
Binocularity ON/OFF Convergence Midget/Parasol Convergence
Three models of columnar organisation in V1 Original Hubel-Wiesel "Ice-C
ube" Model
Cortical
Left Eye
Right Eye
Sub-cortical
m
Radical Model
1m
Midget Parasol
Left Eye
Right Eye
Swirl Model
Figure by MIT OCW.
Striate Cortex Output Cell
Intracortical
LEFT EYE INPUT
Midget ON Midget OFF
Midget ON Midget OFF
Parasol ON Parasol OFF
Parasol ON Parasol OFF
luminance color orientation spatial frequency depth motion
RIGHT EYE INPUT
The ON and OFF Channels
The receptive fields of three major classes of retinal ganglion cells
ON
OFF
ON/OFF
inhibition
inhibition
inhibition
Action potentials discharged by an ON and an OFF retinal ganglion cell Stimulation confined to receptive field center
ON cell
OFF cell Stimulation of the entire receptive field
ON cell OFF cell dark spot
light spot
light stimulation condition time
The midget and parasol channels
MIDGET SYSTEM
PARASOL SYSTEM
neuronal response profile
OFF
ON
time
ON
OFF
Projections of the midget and parasol systems Midget
V1
Mixed
V2
Parasol
w
LGN
P
?
M
MT
V4
Midget Parasol
PARIETAL LOBE
TEMPORAL LOBE
Spatial Frequency H
Processing Capacity
L H
L
Midget System Parasol System
Temporal Frequency H
L L
H
Figure by MIT OCW.
Color vision and adaptation
Basic facts and rules of color vision
1. There are three qualities of color: hue, brightness, saturation 2. There is a clear distinction between the physical and psychological attributes of color: wavelength vs. color, luminance vs. brightness.
3. Peak sensitivity of human photoreceptors (in nanometers): S = 420, M = 530, L = 560, Rods = 500 4. Grassman's laws: 1. Every color has a complimentary which when mixed propery yields gray. 2. Mixture of non-complimentary colors yields intermediates. 5. Abney's law: The luminance of a mixture of differently colored lights is equal to the sum of the luminances of the components. 6. Metamers: stimuli producing different distributions of light energy that yield the same color sensations.
Basic facts about light adaptation 1. Range of illumination is 10 log units. But reflected light yields only a 20 fold change (expressed as percent contrast). 2. The amount of light the pupil admits into the eye varies over a range of 16 to 1. Therefore the pupil makes only a limited contribution to adaptation. 3. Most of light adaptation takes place in the photoreceptors. 4. Any increase in the rate at which quanta are delivered to the eye results in a proportional decrease in the number of pigment molecules available to absorb those quanta . 5. Retinal ganglion cells are sensitive to local contrast differences, not absolute levels of illumination.
The color circle
white
white
Yellow
saturation
Green Red
Blue
black
hue
Response to Different Wavelength Compositions in LGN Blue ON cell Yellow ON cell 90
90
135
135
45
45
Spikes per Second
180
10 20 30 40 50 60
225
0
180
315
20 40 60 80 100
225
270
Red ON cell
90
90
135
135
45
10
225
20
30
315 270
315 270
Green OFF cell
180
0
40
0
180
45
10 20 30 40 50
225
maintained discharge rate
315 270
0
Depth perception
Cues used for coding depth in the brain
Oculomotor cues accommodation vergence
Visual cues Binocular stereopsis
Monocular motion parallax shading interposition size perspective
stereo camera
MOTION PARALLAX, the eye tracks
1
a
2 b
eye movement
a
object motion
1
The eye tracks the circle, which therefore remains stationary on the fovea Objects nearer than the one tracked move at greater velocities on the retinal surface than objects further; the further objects actually move in the opposite direction on the retina.
2
b
Form perception
Three general theories of form perception:
1. Form perception is accomplished by neurons that respond
selectively to line segmens of different orientations..
2. Form perception is accomplished by spatial mapping of
the visual scene onto visual cortex.
3. Form perception is accomplished by virtue of Fourier analysis.
Eye-movement control
superior colliculus
medial eye fields frontal eye fields parietal cortex
visual cortex MEF p
FEF
LIP
SC ce
sts
V1 ls
BS
V2
medial eye fields
frontal eye fields
parietal cortex
superior colliculus ablated
visual cortex MEF
Anterior system
p
FEF
LIP
SC ce
sts
V2 V1
ls BS
Posterior system
Summary of the effects of electrical stimulation:
FACILITATION
V1 & V2, upper V1 & V2, lower V4 LIP FEF
MEF
INTERFERENCE
FIX INCREASE
NO EFFECT
Summary of the effects of the GABA agonist
muscimol and the GABA antagonist bicuculline
Target selection muscimol
V1
INTERFERENCE
FEF
INTERFERENCE
LIP
SC
Visual discrimination muscimol
bicuculline INTERFERENCE
V1
bicuculline
DEFICIT
DEFICIT
FACILITATION
FEF
MILD DEFICIT
NO EFFECT
NO EFFECT
NO EFFECT
LIP
NO EFFECT
NO EFFECT
INTERFERENCE
FACILITATION
Hikosaka and Wurtz
Saccade to new location
A
1. 2. 3. 4.
1 B
V1, V2, V4, IT, LIP, etc.
A
what?
2
C
What are the objects in the scene? Which object to look at? Which object not to look at? Where are the objects in space?
5. When to initiate the saccade?
B
V1, V2, LIP, FEF, MEF
Br a
A
which?
3
C B
in a
V1, V2, LIP
re a
si nv olv ed
A
which not?
4
C B
V1, V2, FEF, SC
A
where?
5
C B A
LIP when?
C
Midget
V1
Auditory
V2
Mixed
?
?
Parasol
system
w
LGN
Somatosensory
P M
Midget Parasol
system
V4
MT Posterior system PARIETAL LOBE
?
TEMPORAL LOBE
Olfactory
system
w
SC
?
BG
rate code
BS
BS
FRONTAL LOBE FEF MEF
SN vector code
system
vector code place code
Vergence system
Accessory optic system
Smooth pursuit
Anterior system
Vestibular
system
Motion perception
Summary of cell types in V1
s1
s5
D
D L
.1 .2 .3 .4 .5 DEGREES OF VISUAL ANGLE
.1
.3
.2
.4
.5
.7 deg
.6
L D
s2 L
D
s6 .1 .2 .3 .4 .5 .6 .7 DEGREES OF VISUAL ANGLE
.1
s3
D
.8
.2
.3
.2
.3
.4
.5
.6
.7
.4
.5
.6
.7
.8
.9
.9
.1
.2
L
.3
.2
.4
L
s4
.1
1.1 deg
D L
L
1.0
deg
s7
D
.8
D
L
L .1
L
.5
.6
.7
D
.8
.9
1.0 deg
L
D .3
.4
.5
.6
deg
CX
D L
D
.1
.2
.3
.4
.5
.6
.7
.8
.9
1.0 1.1
1.2 deg
Figure by MIT OCW.
Major Pathways of the Accessory Optic System (AOS) Velocity response of AOS neurons = 0.1-1.0 deg/sec Number of AOS RGCs in rabbit = 7K out of 350K
2
Cortex 1
Cerebellum
Ant
3 climbing fibers Prime axes of retinal direction-selective neurons
NOT
Inferior Olive Semicircular canals
D 1
M 2,3
Vestibular Nucleus
L
rate code
BS
BS
2,3
Terminal Nuclei
vestibulo-ocular reflex
Effects of lesions on vision
Summary of lesion deficit magnitudes PLGN
MLGN
V4
MT
color vision
severe
none
mild
none
texture perception
severe
none
mild
none
BASIC VISUAL FUNCTIONS
VISUAL CAPACITY
pattern perception
fine
severe
none
mild
none
shape perception
fine
severe
none
mild
none
coarse
mild
none
none
none
brightness perception
none
none
none
none
coarse scotopic vision
none
none
none
none
fine
severe
none
mild
mild
coarse
mild
none
none
mild
fine
severe
none
none
none
coarse
pronounced
none
none
none
contrast sensitivity
INTERMEDIATE
stereopsis
motion perception
none
moderate
none
moderate
flicker perception
none
severe
none
pronounced
choice of "lesser" stimuli
severe severe
none
severe
none
visual learning
not tested
not tested
severe
none
object transformation
not tested
not tested
pronounced
not tested
Prosthetics
Figure by MIT OCW.
The size and location of the regions activated in the monkey V1 by the dotted circle presented in the visual field 90
5 4
135
90
5
45
4
135
45 3
3 2
2 1
1
180
0
225
180
0
315
225
315
270 2
3
4
270
270 270
1
3
2
1
2
3
4
270
270
1
315 225
315 225
0 180
0 180
45
90
4
45
135
90
90
135
90
4
3
2
1
The size and location of the regions activated in the monkey V1 by the dots presented in the visual field 90
256 points
5
135
135
45
4
90
55
45
4 3
3 2
2 1
1
180
0
225
180
0
225
315
315
270 2
3
4
270
270 270
1
3
2
1
2
3
4
270
270
1
315 225
315 225
0 180
0 180
45
90
4
45
135
90
90
135
90
4
3
2
1
Illusions
The Hermann grid illusion
The most widely cited theory purported to explain the illusion:
ON
larger response
ON
smaller response
Due to antagonistic center/surround organization, the activity of ON-center retinal ganglion cells whose receptive fields fall into the intersections of the grid produces a smaller response than those neurons whose receptive fields fall elsewhere.
Differently oriented vertical and horizontal lines reduce illusion
Retinal ganglion cell receptive field layout at an eccentricity of 5 degrees
At the eccentricity of 5 degrees the 0.5 by 0.5 degree visual angle area outlined impinges on 365 midget cells and 50 parasol cells. Half of these are ON and half OFF cells. The layout of the ON cells is shown in B and C.
5mm
5 deg of visual angle
Retinal midget cells
0.5 deg of visual angle
Retinal parasol cells
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