Topics:
1. Basics of eye movements
2. The eye plant and the brainstem nuclei
3. The superior colliculus
4. Visual inputs for saccade generation
5. Cortical structures involved in saccadic eye-movement control
6. The effects of paired electrical and visual stimulation
7. The effects of lesions on eye movement
8. Pharmacological studies
1
5. Cortical areas involved in saccadic
eye-movement control
2
Central Sulcus
MEP
MIP
LIP
STS
FEF
V1
Principalis
Lunate
Arcuate
V4
Image by MIT OpenCourseWare.
3
superior colliculus
medial eye fields
frontal eye fields
parietal cortex
visual cortex
MEF
p
FEF
LIP
SC
ce
sts
V2
V1
ls
BS
4
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
5
6. The effects of paired electrical
and visual stimulation
6
The effect of paired electrical stimulation in the superior colliculus
1 and 2
1 or 2
1
2
1
1+2
SC
ant
post
2
lateral
1
2
medial
1
ant
SC
2
1+2
post
lateral
7
The effect of paired elecectrical stimulation in the left and right colliculi
1
posterior
2
SC
anterior
1
2
1 or 2
1+2
1 and 2
8
Eye movements made to paired targets
The task
The eye movements elicited
Image by MIT OpenCourseWare.
9
7. The effect of lesions on
eye-movement control
10
Informal testing, intact monkey
ce
p
ip
sts
ls
11
Informal testing after superior colliculus ablation
ce
p
sc
ip
sts
ls
12
Single target task
13
Single target task
14
Number of Saccades
Distribution of saccadic latencies in intact monkey
Express
saccades
120
Regular
saccadess
100
80
60
40
20
50
100
150
200
Latency in Milliseconds
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. Courtesy of Elsevier, Inc., http://www.sciencedirect.com. Used with permission.
15
Distribution of saccadic latencies
ten weeks after left superior colliculus lesion
Number of Saccades
Leftward saccades
Rightward saccades
40
Intact representation
40
Ablated representation
30
30
20
20
10
10
50
100
150
200 50
100
150
200
Latency in Milliseconds
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. Courtesy of Elsevier, Inc., http://www.sciencedirect.com. Used with permission.
16
Informal testing after frontal eye field ablation
ce
p
fef
ip
sts
ls
17
Number of saccades
Distribution of saccadic latencies after FEF and MEF lesions
Paired MEF & FEF Lesion
FEF Lesion
50
40
40
30
30
20
20
10
10
N = 407
50
100
150
200
N = 313
50
100
150
200
Time in milliseconds
18
Sequential task
19
Figure removed due to copyright restrictions.
Please see lecture video or Figure 8 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.
20
The effect of FEF and MEF lesions on executing sequential saccades
Figure removed due to copyright restrictions.
Please see lecture video or Figure 9 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.
21
Paired target task, identical targets
22
Paired target task, identical targets
23
Eye movements made to paired targets presented with varied asynchronies
Left 34ms before right
Simultaneous
Right 34ms before left
Image by MIT OpenCourseWare.
24
Reprinted by permission from Macmillan Publishers Ltd: Nature Neuroscience.
Source: Schiller, Peter H., and I-han Chou. "The Effects of Frontal Eye Field and Dorsomedial Frontal Cortex
Lesions on Visually Guided Eye Movements." Nature Neuroscience 1, no. 3 (1998): 248-53. © 1998.
25
Percent saccades to left targets
Saccades made to identical paired targets presented with varied asynchronies
100
90
80
70
60
50
40
30
20
LFEF lesion
wk3
pre-op
wk2
wk16
4yrs
10
0
220 200 180 160 140 120 100 80
Right target first
60
40
20
0
20
40 60 80 100 120 140 160 180 220 220
Left target first
Onset asynchrony in milliseconds
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. Courtesy of Elsevier, Inc., http://www.sciencedirect.com. Used with permission.
26
Percent saccades to left targets
Saccades made to identical paired targets presented with varied asynchronies
100
90
80
70
60
50
40
30
20
10
0
LFEF lesion
RMEF lesion
wk3
wk2
wk16
wk16
wk2
4yrs
pre-op
220 200 180 160 140 120 100 80
Right target first
60
40
20
0
20
40 60 80 100 120 140 160 180 220 220
Left target first
Onset asynchrony in milliseconds
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. Courtesy of Elsevier, Inc., http://www.sciencedirect.com. Used with permission.
27
Informal testing after bilateral superior colliculus and frontal eye field ablation
fef
p
fef
sc
sc
ip
sts
ls
28
Further examination of the effects of microstimulation on eye-movement generation
29
The effects of pairing electrical stimulation
with visual stimulation in four cortical areas Figure removed due to copyright restrictions.
Please see lecture video or Figure 13 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.
30
Experimental procedure:
Map RF
1
Electrically stimulate
2
Present target in RF
3
Stimulate with paired targets
4
Stimulation initiated 30ms after target appearance for 80ms at 200H
31
Percent saccades to target in RF
Percent of time target in RF is chosen, no stimulation
stimulation
90
100
90
80
70
60
180
FRF
270
50
40
0
INTERFERENCE
FACILITATION
30
20
10
0
-30
-20
-10
0
10
20
30
Temporal asynchrony (ms) relative to target in receptive field
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. Courtesy of Elsevier, Inc., http://www.sciencedirect.com. Used with permission.
32
Stimulation added on selected trials
Percent Saccades to Target in RF
V1
100
90
80
70
Lower layers
ON
I
AT
T
LI
I
C
A
F
10uA, 0%
60
50
7.5uA, 0%
40
30
RF
20
No Stimulation
10
0
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
90
100
Temporal asynchrony (ms) relative to target in receptive field
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. Courtesy of Elsevier, Inc., http://www.sciencedirect.com. Used with permission.
33
Stimulation added on selected trials
V1
Percent saccades to target in RF
100
Upper layers
90
90
80
E
C
No stimulation
EN
R
E
F
ER
T
30uA, 5%
IN
70
0
180
60
RF
50
40
270
30
20
10
50uA, 10%
0
-20
-10
0
10
20
30
40
50
Temporal asynchrony (ms) relative to target in receptive field
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. Courtesy of Elsevier, Inc., http://www.sciencedirect.com. Used with permission.
34
Stimulation added on selected trials
Figure removed due to copyright restrictions.
Please see lecture video or Figure 15B 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.
35
Stimulation added on selected trials
Figure removed due to copyright restrictions.
Please see lecture video or Figure 15A 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.
36
Saccadic latencies in LIP with increasing current levels
Figure removed due to copyright restrictions.
Please see lecture video or Figure 16 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.
37
Stimulation added on selected trials
FEF
Percent saccades to target in MF
100
FACILITATION
90
80
25u,A, 45%
70
13uA, 0%
7uA, 0%
60
50
40
30
MF
20
No Stimulation
10
0
80
70
60
50
40
30
20
10
0
-10
-20
-30
Temporal asynchrony (ms) relative to target in motor field
38
Stimulation added on selected trials
MEF
Percent saccades to target in RF
100
90
FACILITATION
50uA, 65%
80
70
38uA, 5%
60
50
40
30
25uA, 0%
No Stimulation
20
TZ
10
0
-30
-20
-10
0
10
20
30
Temporal asynchrony (ms) relative to target in terminal zone
39
medial eye fields
MEF
p
ce
sts
ls
40
MEF
One target in motor field
Fixation spot in motor field
Stimulation facilitates
Stimulation prolongs fixation time
1
no stimulation
2
stimulation
target onset
1 second
41
Summary of the effects of electrical stimulation:
FACILITATION
INTERFERENCE
FIX INCREASE
NO EFFECT
V1 & V2, upper
V1 & V2, lower
V4
LIP
FEF
MEF
42
8. Pharmacological studies
43
Pharmacological manipulation
electrodes for recording, stimulation
and injection
ce
p
FEF
SC
LIP
ip
sts
ls
V1
44
Bicuculline: a GABA antagonist. Therefore
when infused inhibition is decreased
Muscimol: a GABA agonist. Therefore
when infused inhibition is increased
45
Effects of stimulation and injection in the superior colliculus
stimulation/injection electrode
medial
anterior
Electrical stimulation
stimulation elicited saccades
Muscimol injection
inhibition of saccades with vectors
represented at injected site
Bicuculline injection
spontaneous saccades with vectors
represented at injected site
Hikosaka and Wurtz
46
To assess the role of inhibitory circuits in
cortex two behavioral tasks were used:
1. Paired target task
2. Visual discrimination task (oddity)
47
Percent saccades to target in RF
Paired target task
90
100
90
80
70
60
0
180
FRF
270
50
40
INTERFERENCE
FACILITATION
30
20
10
0
-30
-20
-10
0
10
20
30
Temporal asynchrony (ms) relative to target in receptive field
48
The oddity task
49
The oddity task
50
The effects of muscimol injection in cortex
51
Muscimol injection in V1, paired target task
Figure removed due to copyright restrictions.
Please see lecture video or the top panel of Figure 2 from Schiller, Peter H., and
Edward J. Tehovnik. "Cortical Inhibitory Circuits in Eye‐movement Generation."
European Journal of Neuroscience 18, no. 11 (2003): 3127-33.
52
Muscimol injection in FEF, paired target task
Figure removed due to copyright restrictions.
Please see lecture video or the middle panel of Figure 2 from Schiller, Peter H., and
Edward J. Tehovnik. " Cortical Inhibitory Circuits in Eye‐movement Generation."
European Journal of Neuroscience 18, no. 11 (2003): 3127-33.
53
Muscimol injection in LIP, paired target task
Figure removed due to copyright restrictions.
Please see lecture video or the bottom panel of Figure 2 from Schiller, Peter H., and
Edward J. Tehovnik. "Cortical Inhibitory Circuits in Eye‐movement Generation."
European Journal of Neuroscience 18, no. 11 (2003): 3127-33.
54
Muscimol injection, oddities task
Figure removed due to copyright restrictions.
Please see lecture video or Figure 3 from Schiller, Peter H., and Edward J. Tehovnik.
"Cortical Inhibitory Circuits in Eye‐movement Generation." European Journal of
Neuroscience 18, no. 11 (2003): 3127-33.
55
The effects of bicuculline injection in cortex
56
Bicuculline injection in V1, paired target task
Image removed due to copyright restrictions.
Please see lecture video or the top panel of Figure 4 from Schiller, Peter H., and Edward
J. Tehovnik. "Cortical Inhibitory Circuits in Eye‐movement Generation." European Journal
of Neuroscience 18, no. 11 (2003): 3127-33.
57
Bicuculline injection in FEF, paired target task
Image removed due to copyright restrictions.
Please see lecture video or the middle panel of Figure 4 from Schiller, Peter H., and Edward
J. Tehovnik. "Cortical Inhibitory Circuits in Eye‐movement Generation." European Journal of
Neuroscience 18, no. 11 (2003): 3127-33.
58
The effect of local bicuculline injection in the FEF
on eye movements made to three targets
Figure removed due to copyright restrictions.
Please see lecture video or middle panel of Figure 7 from Schiller, Peter H., and Edward J.
Tehovnik. "Neural Mechanisms Underlying Target Selection with Saccadic Eye Movements."
Progress in Brain Research 149 (2005): 157-71.
59
Bicuculline injection in LIP, paired target task
Image removed due to copyright restrictions.
Please see lecture video or the bottom panel of Figure 4 from Schiller, Peter H., and
Edward J. Tehovnik. "Cortical Inhibitory Circuits in Eye‐movement Generation."
European Journal of Neuroscience 18, no. 11 (2003): 3127-33.
60
Bicuculline injection, oddities task
Figure removed due to copyright restrictions.
Please see lecture video or Figure 5 from Schiller, Peter H., and Edward J. Tehovnik.
"Cortical Inhibitory Circuits in Eye‐movement Generation." European Journal of
Neuroscience 18, no. 11 (2003): 3127-33.
61
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
62
Saccade to new location
A
1.
2.
3.
4.
1
B
V1, V2, V4,
IT, LIP, etc.
A
2
C
what?
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
A
which?
Br
ain
3
C
B
V1, V2, LIP
ar
ea
s
A
which not?
4
C
B
inv
olv
ed
V1, V2,
FEF, SC
A
where?
5
C
B
A
LIP
when?
C
63
Summary wiring diagrams
64
Midget
V1
V2
Mixed
?
?
Parasol
w
LGN
P
M
Midget
Parasol
V4
MT
Posterior
system
PARIETAL LOBE
w
SC
?
BS
TEMPORAL LOBE
BG
rate code
BS
?
FRONTAL LOBE
FEF
MEF
SN
vector code
vector code
place code
Anterior
system
65
Midget
V1
Auditory
V2
Mixed
?
?
Parasol
system
w
LGN
Somatosensory
P
M
V4
MT
Posterior
system
Midget
Parasol
PARIETAL LOBE
?
TEMPORAL LOBE
system
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
66
Summary:
1. Two major cortical systems control visually guided saccadic eye movements: The anterior
and the posterior.
2. The anterior system has direct access to the brainstem whereas the posterior
system passes through the colliculus.
3. Inhibitory circuits, as from the substantia nigra and in the frontal eye fields, are
essential for generating properly directed saccadic eye-movements.
4. Areas V1, V2, FEF, LIP and SC carry a vector code. MEF carries a place code.
5. Paired ablation of the FEF and SC eliminates visually guided saccadic eye movements.
6. The posterior system is essential for producing express saccades.
7. The FEF plays a central role in the planning of saccadic sequences and target selection.
8. The posterior system is important for object identification, for deciding where to look
and where not to look. LIP in addition is important for deciding when to look. The FEF
and MEF contribute to where to look.
9. The role of the medial eye fields remains a puzzle. It may be involved in hand-eye
coordination, in establishing spatial relationships and in visuo-motor learning. 67
The end
Thank you
68
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9.04 Sensory Systems
Fall 2013
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