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
rods cones
photo- receptors
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 periphery
3 4 2 3 1 2 1 Figure removed due to copyright restrictions.
6 layers 4 layers
Please see lecture video or Figure 4A of Schiller, Peter H., midget/parasol ratio: fovea: 8 to 1 periphery: 1 to 1 and Edward J. Tehovnik. "Visual Prosthesis." Perception 37, no. 10 (2008): 1529.
midget
parasol
fovea periphery eccentricity
7 MIP MEP Central Sulcus LIP STS FEF
V1
Principalis Lunate Arcuate V4
Image by MIT OpenCourseWare.
8 Cortical projections from LGN
K1
M
P K2
6 345 2 1 V1
Lamina: 3-6 = parvo 1-2 = magno interlaminar
LGN © Pion Ltd. and John Wiley & Sons, Inc.. All rights reserved. This content is excluded from our Creative Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/. 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-Cube" Model
Cortical Midget Left Eye Right Eye Parasol Sub-cortical Radical Model
1 mm
Left Eye Right Eye Swirl Model
Image by MIT OpenCourseWare. 11 Striate Cortex Output Cell
Intracortical
Midget ON Midget ON Midget OFF Midget OFF LEFT EYE RIGHT EYE INPUT INPUT Parasol ON Parasol ON Parasol OFF Parasol OFF
luminance color orientation spatial frequency depth motion
12 Extrastriate cortex
13 V1 STS LIP MIP Lunate Image by MIT OpenCourseWare.
Central Sulcus V4 Arcuate MEP FEF Principalis 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
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
ON OFF 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
VISUAL CAPACITY PLGN MLGN V 4 MT color vision severe none mild none
texture perception severe none mild none
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
contrast sensitivity fine severe none mild mild coarse mild none none mild BASIC VISUAL FUNCTIONS stereopsis fine severe none none none
coarse pronounced none none none
motion perception none moderate none moderate
flicker perception none severe none pronounced
choice of "lesser" stimuli severesevere none severe none
visual learning not tested not tested severe none
object transformation not tested not tested pronounced not tested INTERMEDIATE INTERMEDIATE
24 Spatial Frequency H The midget system extends the range of visual processing in the spatial frequency and wavelength range.
L
L H
Midget System Parasol System Processing Capacity 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
G R 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 45 135 45 Spikes per Second
180 0 180 0 10 20 30 40 50 60 20 40 60 80 100
225 315 225 315
270 270
Green OFF cell Red ON cell 90 90
135 45 135 45
180 0 180 0 10 20 30 40 10 20 30 40 50
225 315 225 315 maintained discharge rate 270 270 29 Response of a retinal ganglion cell at various background adaptation levels
400
300 background log cd/m2 -5 -4 -2-3 -1 0
200 Discharge rate (spikes/sec) rate Discharge 100
0 -5 -4 -3 -2 -1 0 Test flash (log cd/m2)
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 Visual cues
accommodation Binocular vergence 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 2 b 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.
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 45 5 45 4 3 2 disks across 1 midline 0 0
-45 -45
-90 -90
-45
0
45 0.25 0.25 0.5 0.5 1 90 1 2 2 4 7 7 4
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 neurons whose receptive fields fall elsewhere. Image is in public domain.
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
VISUAL CAPACITY PLGN MLGN V 4 MT color vision severe none mild none
texture perception severe none mild none
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
contrast sensitivity fine severe none mild mild coarse mild none none mild BASIC VISUAL FUNCTIONS stereopsis fine severe none none none
coarse pronounced none none none
motion perception none moderate none moderate
flicker perception none severe none pronounced
choice of "lesser" stimuli severesevere none severe none
visual learning not tested not tested severe none
object transformation not tested not tested pronounced not tested INTERMEDIATE INTERMEDIATE
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 Visual discrimination
muscimol bicuculline muscimol bicuculline
V1 INTERFERENCE INTERFERENCE V1 DEFICIT DEFICIT
FEF INTERFERENCE FACILITATION FEF MILD DEFICIT NO EFFECT
LIP NO EFFECT NO EFFECT LIP NO EFFECT NO EFFECT
SC 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 V 1 V Auditory Mixed V2 ? system Parasol ?
w
LGN P Somatosensory M MT V system 4 ? Posterior Midget system Parasol
PARIETAL LOBE TEMPORAL LOBE Olfactory system w SC BG rate code FRONTAL LOBE SN BS vector code FEF MEF Smooth pursuit BS system vector code Anterior place code system
Vergence Accessory Vestibular system optic system system
60 Motion perception
61 Summary of cell types in V1 s1 D s5 D L .1 .2 .3 .4 .5 .1 .2 .3 .4 .5 .6 .7 deg DEGREES OF VISUAL ANGLE L D
s2 L D
s6 D L .1 .2 .3 .4 .5 .6 .7 .8 DEGREES OF VISUAL ANGLE
.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 1.1 deg
D s3 L L
.1 .2 .3 .4 .5 .6 .7 .8 .9 deg
s7 D D L L
.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 deg L D s4 L L D
.1 .2 .3 .4 .5 .6 deg CX D D L
.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
Cortex 2 1 Cerebellum Ant 3
climbing fibers Prime axes of retinal NOT direction-selective neurons
Inferior Olive D Semicircular 1 canals
M 2,3 Vestibular L Nucleus rate code 2,3 BS Terminal BS Nuclei
vestibulo-ocular reflex 64 MIT OpenCourseWare http://ocw.mit.edu
9.04 Sensory Systems Fall 2013
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