The visual and oculomotor systems
Peter H. Schiller, year 2013
Review,
the visual and oculomotor systems
1
Basic wiring of the visual system
2
Primates
Image removed due to copyright restrictions.
Please see lecture video or Figure 3 from Schiller, Peter H., and Edward J. Tehovnik.
"Visual prosthesis." Perception 37, no. 10 (2008): 1529.
3
Retina and LGN
4
sign inverting synapse
sign conserving synapse
pigment epithelium
cones
rods
photoreceptors
Bipolar glutamate receptors:
ON = mGluR6
OFF = mGluR 1 & 2
OPL
gap junction
cone horizontal
H
ON
OFF
bipolars
ON
glycinergic
synapse
IPL
AII
ON
OFF
amacrine
ganglion cells
incoming light
to CNS
5
Coronal section of monkey LGN
fovea
6
5
4
3
2
1
Figure removed due to copyright restrictions.
6 layers
periphery
4
3
2
1
4 layers
midget/parasol ratio:
fovea: 8 to 1
periphery: 1 to 1
Please see lecture video or Figure 4A of Schiller, Peter H.,
and Edward J. Tehovnik. "Visual Prosthesis." Perception
37, no. 10 (2008): 1529.
midget
parasol
periphery
fovea
eccentricity
6
Visual cortex
7
Central Sulcus
MEP
MIP
LIP
STS
FEF
V1
Principalis
Lunate
Arcuate
V4
Image by MIT OpenCourseWare.
8
Cortical projections from LGN
K1
M
P
K2
6
5 4
3
V1
2 1
Lamina:
3-6 = parvo
1-2 = magno
interlaminar
LGN
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9
Transforms in V1
Orientation
Direction
Spatial Frequency
Binocularity
ON/OFF Convergence
Midget/Parasol Convergence
10
Three models of columnar organization 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
Image by MIT OpenCourseWare.
11
Striate Cortex Output Cell
Intracortical
LEFT EYE
INPUT
Midget ON
Midget OFF
Midget ON
Midget OFF
Parasol ON
Parasol OFF
Parasol ON
Parasol OFF
RIGHT EYE
INPUT
luminance
color
orientation
spatial frequency
depth
motion
12
Extrastriate cortex
13
Central Sulcus
MEP
MIP
LIP
STS
FEF
V1
Principalis
Lunate
Arcuate
V4
Image by MIT OpenCourseWare.
Major cortical visual areas:
Occipital
V1
V2
V3
V4
MT
Temporal
Parietal
Frontal
IT
(medial temporal)
(inferotemporal)
LIP (lateral intraparietal)
VIP (ventral intraparietal)
MST (medial superior temporal)
FEF
(frontal eye fields)
15
The ON and OFF Channels
16
The receptive fields of three major
classes of retinal ganglion cells
ON
OFF
ON/OFF
inhibition
inhibition
inhibition
17
Action potentials discharged by an ON and an OFF retinal ganglion cell
Figure removed due to copyright restrictions.
Please see lecture video or Figure 2A of Schiller, Peter H., and Edward
J. Tehovnik. "Visual Prosthesis." Perception 37, no. 10 (2008): 1529.
18
The 2-amino-4-phosphonobutyrate (APB) experiments
blocking the ON channel:
1. No effect on center-surround antagonism and on
orientation and direction selectivities in V1.
2. Deficit in detecting light increment but not
light decrement.
19
The central conclusion:
The ON and OFF channels have emerged in
the course of evolution to enable organisms
to process both light incremental and light
decremental information rapidly and effectively.
20
The midget and parasol channels
21
MIDGET SYSTEM
PARASOL SYSTEM
Neuronal response profile
OFF
ON
ON
OFF
time
22
Projections of the midget and parasol systems
Midget
V1
Mixed
V2
Parasol
w
LGN
P
?
M
MT
V4
Midget
Parasol
PARIETAL LOBE
TEMPORAL LOBE
23
Summary of PLGN and MLGN 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
24
Spatial Frequency
The midget system extends
the range of visual processing
in the spatial frequency and
wavelength range.
Processing Capacity
H
L
H
L
Midget System
Parasol System
Temporal Frequency
H
The parasol system extends
the range of visual processing
in the temporal frequency range.
L
L
H
Image by MIT OpenCourseWare.
25
Color vision and adaptation
26
The color circle
Y
Hue
R
G
Saturation
B
Image by MIT OpenCourseWare.
27
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.
28
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
45
180
10 20 30 40 50
225
maintained discharge rate
0
315
270
29
Response of a retinal ganglion cell at various background adaptation levels
400
background
log cd/m2
Discharge rate (spikes/sec)
300
-5
-4
-3
-2
-1
0
200
100
0
-5
-4
-3
-2
Test flash (log cd/m2)
-1
0
Image by MIT OpenCourseWare.
30
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.
31
Depth perception
32
Cues used for coding depth in the brain
Oculomotor cues
accommodation
vergence
Visual cues
Binocular
stereopsis
Monocular
motion parallax
shading
interposition
size
perspective
33
Autostereogram
Image removed due to copyright restrictions.
Please see lecture video or the autostereogram from The Magic Eye, Volume I:
A New Way of Looking at the World. Andrews McMeel Publishing, 1993.
Masayuki Ito, 1970, Chris Tyler, 1990
34
MOTION PARALLAX, the eye tracks
1
a
2
b
eye movement
object motion
a
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
35
36
37
37
38
Form perception
39
Three general theories of form perception:
1. Form perception is accomplished by neurons that respond
selectively to line segments 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.
40
Form perception with little information about orientation of line segments
Image removed due to copyright restrictions.
Please refer to lecture video.
41
Cortical layout of neurons activated by disks
disks in one
hemifield
Image by MIT OpenCourseWare.
42
Cortical layout of neurons activated by disks
7 90
6
5
4
3
2
1
45
45
disks across
midline
0
0
-45
-45
-90
-90
-45
0
45
0.25
0.25
0.5
0.5
1
2
90
4
7
7
4
2
1
Image by MIT OpenCourseWare.
43
Prosthetics
44
Image removed due to copyright restrictions.
Please see lecture video or Figure 5 from Schiller, Peter H., and Edward J. Tehovnik.
"Visual prosthesis." Perception 37, no. 10 (2008): 1529.
45
Image removed due to copyright restrictions.
Please see lecture video or Figure 7 from Schiller, Peter H., and Edward J. Tehovnik.
"Visual prosthesis." Perception 37, no. 10 (2008): 1529.
46
Image removed due to copyright restrictions.
Please see lecture video or Figure 9 from Schiller, Peter H., and Edward J. Tehovnik.
"Visual prosthesis." Perception 37, no. 10 (2008): 1529.
47
Illusions
48
The Hermann grid illusion
The most widely cited theory
purported to explain the illusion:
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
Image is in public domain.
neurons whose receptive fields fall elsewhere.
49
Differently oriented vertical and horizontal lines reduce illusion
Figure removed due to copyright restrictions.
Please see lecture video or Schiller PH, Carvey CE (2005). "The
Hermann Grid Illusion Revisited." Perception 34 (11): 1375–97.
50
Retinal ganglion cell receptive field layout at an eccentricity of 5 degrees
Figure removed due to copyright restrictions.
Please see lecture video or Schiller PH, Carvey CE (2005). "The
Hermann Grid Illusion Revisited." Perception 34 (11): 1375–97.
51
After-effect illusions explained by
the facts and rules of adaptation.
interocular experiments
52
Effects of lesions on vision
53
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
54
Eye-movement control
55
Electrical stimulation triggering eye movements:
Figure removed due to copyright restrictions.
Please see lecture video or Figure 2 from Schiller, Peter H., and Edward J.
Tehovnik. "Look and See: How the Brain Moves Your Eyes About."
Progress in Brain Research 134 (2001): 127-42.
56
Electrical stimulation triggering eye movements:
Figure removed due to copyright restrictions.
Please see lecture video or Figure 3 from Schiller, Peter H., and Edward J.
Tehovnik. "Look and See: How the Brain Moves Your Eyes About."
Progress in Brain Research 134 (2001): 127-42.
57
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
58
Figure removed due to copyright restrictions.
Please see lecture video or Figure 17 from Schiller, Peter H., and Edward J.
Tehovnik. "Look and See: How the Brain Moves Your Eyes About."
Progress in Brain Research 134 (2001): 127-42.
59
Midget
V1
Auditory
V2
Mixed
?
?
Parasol
system
w
LGN
Somatosensory
P
M
V4
MT
Posterior
system
Midget
Parasol
PARIETAL LOBE
system
?
TEMPORAL LOBE
Olfactory
system
w
SC
BG
rate code
BS
BS
vector code
FRONTAL LOBE
FEF
MEF
SN
system
vector code
place code
Vergence
system
Accessory
optic system
Smooth pursuit
Anterior
system
Vestibular
system
60
Motion perception
61
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
.2
.3
.2
.3
.4
.5
.6
.7
.4
.5
.6
.7
.8
.9
.9
1.0
1.1 deg
deg
s7
D
.8
D
L
L
.1
L
D
.8
D
L
L
.1
.2
.3
.4
.5
.6
.7
.8
.9
1.0 deg
L
D
s4
L
.1
.2
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
Image by MIT OpenCourseWare.
62
The central role of the parasol system
in motion processing and in the
perception of apparent motion.
63
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
64
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9.04 Sensory Systems
Fall 2013
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