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The Midget and Parasol Channels
1
Retinal ganglion cells, cross section, Golgi label
Image removed due to copyright restrictions.
Please refer to lecture video or Figure 4 from Schiller, Peter H. "Parallel information processing channels created in the retina." Proceedings of the National Academy of Sciences 107, no. 40
(2010): 17087-17094.
by Polyak2
Images removed due to copyright restrictions.
3
Please refer to lecture video or Figure 2c and 3c of Watanabe, M., and R. W. Rodieck. "Parasol and midget ganglion cells of the primate retina."
J 189, no. 3 (1989): 434-454.
Projections of the retinal ganglion cells
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Cortical projections from LGN
123456
1-2 = magno3-6 = parvo
P
M
K2V1
Lamina:
interlaminar
LGN
K1 ?
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The central connections of the midget
and parasol channels
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14
60-
40-
20-
80-
60-
40-
20-
80-
60-
40-
80-
60-
40-
20-
20-
80-
60-
40-
20-Sp
ikes
per
bin
Normal
Parvo Injection
Magno Injection
Paired Injection
Recovery
Vl complex cell response to moving light bar
Image by MIT OpenCourseWare.
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Time (msec)Time (msec)
00 15891593
46 36
46 36
BeforeBlock
AfterBlock
Magno Block Parvo Block
Recording in V4
Image by MIT OpenCourseWare.
16
Time (msec)Time (msec)00
BeforeBlock
AfterBlock
Magno Block Parvo Block
59
59
179
179
963 963
Recording in MT
Image by MIT OpenCourseWare.
1.0
0.8
0.6
0.4
0.2
0.0
V4 MT
Parvocellular BlockMagnocellular Block
Aver
age
bloc
king
inde
x
18
Image by MIT OpenCourseWare.
Lesion studies
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Behavioral procedures
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The lesions
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Example of LGN lesions with ibotenic acid
Images removed due to copyright restrictions.
27
Please refer to lecture video or Figure 4 of Schiller, Peter H., Nikos K. Logothetis, and Eliot R. Charles. "Role of color-opponent and broad-band channels in vision."
V 5, no. 4 (1990): 312-346.
PERCEPTUAL FUNCTIONS TESTED
Contrast Sensitivity Color Pattern
Texture
Shape
Stereopsis Flicker
Motion
Brightness
Scotopic Vision
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Contrast sensitivity
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Contrast Sensitivity
0.1
0.2
0.3
Con
trast 0.4 Normal
MLGN Lesion0.5 PLGN Lesion
0.6
0.7
0.8
0.9
1 1.5 2 2.5 3
Spatial Frequency (cy/deg)
Image by MIT OpenCourseWare.
Color vision
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36
100
90
80
70
60
50
40
30
20
10
0Normal PLGN MLGN
Seneca
Color DiscriminationPe
rcen
t Cor
rect
Image by MIT OpenCourseWare.
Brightness perception
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The perception of brightness in photopic vision
Images removed due to copyright restrictions.
39
Please refer to lecture video or Figure 16b,d of Schiller, Peter H., Nikos K. Logothetis, and Eliot R. Charles. "Role of color-opponent and broad-band channels in vision."
V 5, no. 4 (1990): 312-346.
The perception of brightness in scotopic vision
Images removed due to copyright restrictions.
40
Please refer to lecture video or Figure 13 of Schiller, Peter H., Nikos K. Logothetis, and Eliot R. Charles. "Role of color-opponent and broad-band channels in vision."
V 5, no. 4 (1990): 312-346.
Pattern and texture perception
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44
Texture Pattern
N P MN P M
100
9080
70
60
5040
30
20
10
Perc
ent C
orre
ct
Texture and Pattern Discrimination
Image by MIT OpenCourseWare.
Stereoscopic depth perception
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46
Images removed due to copyright restrictions.
47
Please refer to lecture video or Figure 1 of Schiller, Peter H., Geoffrey L. Kendall, Michelle C. Kwak,and Warren M. Slocum. "Depth perception, Binocular Integration and Hand-Eye Coordination in Intact and Stereo Impaired Human Subjects." 3:210.
Stereoscopic depth perception
Images removed due to copyright restrictions.
48
Please refer to lecture video or Figure 22a,b of Schiller, Peter H., Nikos K. Logothetis, and Eliot R. Charles. "Role of color-opponent and broad-band channels in vision."
V 5, no. 4 (1990): 312-346.
Motion perception
49
53
V4 Lesion
Normal
Normal
Latencies:Normal = 318msMT Lesion = 362ms
Latencies:Normal = 234msMT Lesion =278ms
Eager
100
90
80
70
60
50
40
30
20
10
100
90
80
70
60
50
40
30
20
10
6 8 1210
6 8 12 1410
Percent Luminance Contrast
MT Lesion
Perc
ent C
orre
ct
Zeno
esion
Image by MIT OpenCourseWare.
Motion detection
The perception of flicker
54
57
90
80
70
60
50
40
30
20
10
0
5 8 10 15 20Flicker rate (Hz)
Flicker DetectionPe
rcen
t Cor
rect
Green Flicker
Normal
V4 LesionMT Lesion
Peachy
Red/Green Flicker
5 8 11 14 17 20 23 26
Image by MIT OpenCourseWare.
Flicker perception
Functions of the midget and parasol systems:
The midget system : color texture fine form fine stereo
The parasol system: fast flicker fast, low contrast motion
Both Systems: brightness coarse form coarse stereo slow flicker slow, high contrast motion scotopic vision
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60
H
H
H
H
L
L
L
L
Proc
essi
ng C
apac
ity
Spatial Frequency
Temporal Frequency
Parasol SystemMidget System
Image by MIT OpenCourseWare.
Summary: 1. Two major channels originating in the retina are the midget and the parasol.
2. In central retina the receptive field center of midget RGC and parvocellular LGN cells is compised of a single cone.
3. Parasol cells have much larger receptive fields; the cone input is mixed in both the center and the surround.
4. The midget and parasol cell ratio from center to periphery changes from 8 to 1 to 1 to 1.
5. The midget and parasol systems converge on some of the cells in V1.
6. V4 receives input from both the midget and parasol cells.
7. The major input to MT is from the parasol cells.
8. The midget system extends the range of vision in the wavelength and high spatial frequency domains
9. The parasol system extends the range of vision in the high temporal frequency domain.
61
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9.04 Sensory Systems Fall 2013
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