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
3
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.
Retina and LGN
4
sign inverting synapse sign conserving synapse
receptors
pigment epithelium
incoming light
photo-
conesrods
ON OFF ONbipolars
ON OFF
ganglion cells
to CNS
Hcone horizontal
amacrine
AII
IPL
amacrine
AII
OPL
rods
ON OFF ONbipolars
ON OFF
ganglion cells
to CNS
Hcone horizontal
receptors
pigment epithelium
incoming light
photo-
cones
gap junction glycinergic synapse
Bipolar glutamate receptors: ON = mGluR6 OFF = mGluR 1 & 2
5
fovea
6
5
4
3 2 1
periphery4 3 2 1
6 layers 4 layers
midget/parasol ratio: fovea: 8 to 1 periphery: 1 to 1
midget
parasol
fovea periphery
eccentricity
Coronal section of monkey LGN
Figure removed due to copyright restrictions.
6
Please see lecture video or Figure 4A of Schiller, Peter H.,
and Edward J. Tehovnik. "Visual Prosthesis." Perception37, no. 10 (2008): 1529.
Visual cortex
7
8
Central Sulcus
V1
Lunate
V4
LIPSTS
Principalis
Arcuate
MIPMEP
FEF
Image by MIT OpenCourseWare.
123456
1-2 = magno3-6 = parvo
P
M
K2
LGN
V1
Lamina:
interlaminar
K1
Cortical projections from LGN
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Transforms in V1
Orientation Direction Spatial Frequency Binocularity ON/OFF Convergence
Midget/Parasol Convergence
10
11
Original Hubel-Wiesel "Ice-Cube" Model
Left Eye Right Eye
Left Eye Right Eye
Swirl Model
Sub-cortical
Cortical
Radical Model
MidgetParasol
1 m
m
Image by MIT OpenCourseWare.
Three models of columnar organization in V1
Striate Cortex Output Cell
Intracortical
Midget ON Midget ON Midget OFFMidget OFF RIGHT EYE
INPUT LEFT EYE
INPUT Parasol ONParasol ON Parasol OFF Parasol OFF
luminance color
orientation spatial frequency
depth motion
12
Extrastriate cortex
13
Central Sulcus
V1
Lunate
V4
LIPSTS
Principalis
Arcuate
MIPMEP
FEF
Image by MIT OpenCourseWare.
Major cortical visual areas:
Occipital V1 V2 V3 V4 MT (medial temporal)
Temporal IT (inferotemporal)
Parietal LIP (lateral intraparietal) VIP (ventral intraparietal) MST (medial superior temporal)
Frontal FEF (frontal eye fields)
15
The ON and OFF Channels
16
The receptive fields of three major classes of retinal ganglion cells
OFF
inhibition
ON
inhibition
ON/OFF
inhibition
17
Action potentials discharged by an ON and an OFF retinal ganglion cell
Figure removed due to copyright restrictions.
18
Please see lecture video or Figure 2A of Schiller, Peter H., and Edward
J. Tehovnik. "Visual Prosthesis." Perception 37, no. 10 (2008): 1529.
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
ON OFF ON OFF
time 22
Projections of the midget and parasol systems
Midget
P
Midget
1V
MT
Mixed
Parasol
w
?
Parasol
LGN M
PARIETAL LOBE TEMPORAL LOBE
2
V4
V2V
23
MTV 4
mild
mild
mild
mild
mild
mild
none none
none none
none none
none
none
none
none
none
none none
none none
none
none
moderate
mild
pronounced
severe none
none
not tested
severe
severe
pronounced
color vision
VISUAL CAPACITY PLGN MLGN
coarse scotopic vision
brightness perception
contrast sensitivity
motion perception
flicker perception
fine
coarse
stereopsis fine
coarse
pattern perception
shape perception
texture perception
fine coarse
severe
severe
severe
severe
severe
severe
severe
mild
mild
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
moderate
pronounced
fine
choice of "lesser" stimuli
not testedvisual learning
not tested
not tested
not tested
nonesevere
object transformation
INTE
RM
EDIA
TE
BA
SIC
VIS
UA
L FU
NC
TIO
NS
Summary of PLGN and MLGN lesion deficit magnitudes
24
The midget system extends the range of visual processing in the spatial frequency and wavelength range.
The parasol system extends the range of visual processing in the temporal frequency range.
25
H
H
H
H
L
L
L
L
Proc
essi
ng C
apac
itySpatial Frequency
Temporal Frequency
Parasol SystemMidget System
Image by MIT OpenCourseWare.
Color vision and adaptation
26
The color circle
27
Saturation
Y
B
RG
Hue
Image by MIT OpenCourseWare.
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
30 40 0
45135
180
225 315
270
50 40 60 80 0
45135
180
225 315
270
Spikes per Second
20 100 6010 20
Green OFF cell Red ON cell 90 90
20 0
45135
180
225 315
270
10 20 30 40 0
45135
180
225 315
270maintained discharge rate
10 5030 40
29
30
400
300
200
100
0-5 -4 -3 -2 -1 0
Dis
char
ge ra
te (s
pike
s/se
c) 0-1-2-3-4-5backgroundlog cd/m2
Test flash (log cd/m2)
Image by MIT OpenCourseWare.
Response of a retinal ganglion cell at various background adaptation levels
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 Visual cues
accommodation vergence
Binocular stereopsis
Monocular motion parallax
shading interposition
size perspective
33
Autostereogram
Image removed due to copyright restrictions.
Masayuki Ito, 1970, Chris Tyler, 1990
34
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.
MOTION PARALLAX, the eye tracks
object motion
1
2
a
b
1
2
a
b eye movement
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.
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.
41
Please refer to lecture video.
Cortical layout of neurons activated by disks
disks in one hemifield
42Image by MIT OpenCourseWare.
Cortical layout of neurons activated by disks
disks across midline
43
123456
907
0
-45
-90
-45
0
45
0.250.5
1 2 4 790
45
0
-45
-90
7 4 21
0.50.25
45
Image by MIT OpenCourseWare.
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
Image is in public domain.
49
The most widely cited theorypurported to explain the illusion:
Due to antagonistic center/surround organization, the activity ofON-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
50
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
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.
After-effect illusions explained by the facts and rules of adaptation.
interocular experiments
52
Effects of lesions on vision
53
severe
Summary of lesion deficit magnitudes
VISUAL CAPACITY PLGN MLGN V 4 MT IN
TER
MED
IATE
B
ASI
C V
ISU
AL
FUN
CTI
ON
S
color vision severe none mild none
texture perception severe none mild none
pattern perception fine severe none mild none
shape perception fine coarse
severe none mild none
mild none none none
brightness perception none none none none
coarse scotopic vision none none none none
contrast sensitivity fine
coarse
severe none mild mild
mild none none mild
stereopsis fine
coarse
severe none none none
pronounced none none none
motion perception none moderate none moderate
flicker perception none severe none pronounced
choice of "lesser" stimuli 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.
56
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.
Electrical stimulation triggering eye movements:
Figure removed due to copyright restrictions.
57
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.
Summary of the effects of the GABA agonist muscimol and the GABA antagonist bicuculline
Target selection Visual discrimination
muscimol bicuculline muscimol bicuculline
INTERFERENCE INTERFERENCE
NO EFFECT NO EFFECT
FACILITATION INTERFERENCE
V1 DEFICIT V1
FEF MILD DEFICIT
DEFICIT
FEF
LIP NO EFFECT
NO EFFECT
LIP NO EFFECT
INTERFERENCE FACILITATION Hikosaka and Wurtz SC
58
Figure removed due to copyright restrictions.
59
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.
BS
Auditory system
P
PARIETAL LOBE TEMPORAL LOBE
2
V4
V
Midget
1V
w SC
SN FRONTAL LOBE FEF MEFBS
BG
rate code
vector code
place code
vector code
Midget
w
Parasol
LGN M
Anterior system
2V??
Mixed
?Posterior system
Parasol
MT Somatosensory
system
Olfactory system
Smooth pursuit system
Vergence Accessory Vestibular system optic system system
60
Motion perception
61
62
CXDL
L
LL
L
L
L
L
L
L
L
D
D
D
D
D
D
D
D
D
.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 1.1 1.2 deg
.1 .2 .3 .4 .5
.1 .2 .3 .4 .5 .6 .7 .8
.1 .2 .3 .4 .5 .6 .7 .8 .9
.4.1 .2 .3 .5 .6
.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 deg
.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 deg
deg
deg
1.1
.1 .2 .3 .4 .5 .6 .7 deg
L
D
D
s6
s7
s5s1
s2
s3
s4
DEGREES OF VISUAL ANGLE
DEGREES OF VISUAL ANGLE
Image by MIT OpenCourseWare.
Summary of cell types in V1
The central role of the parasol system in motion processing and in the perception of apparent motion.
63
BS
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
12
3
Cortex Cerebellum
Ant
climbing fibers Prime axes of retinal
direction-selective neurons
Inferior Olive D
M
L
1
2,3
2,3
NOT
Semicircular canals
Vestibular Nucleus
rate code
Terminal BS Nuclei
vestibulo-ocular reflex 64
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9.04 Sensory SystemsFall 2013
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