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Max Planck Institute for Human Cognitive and Brain Sciences
The role of the posterior prefrontal cortex in task
preparation
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Max Planck Institute for Human Cognitive and Brain Sciences
Jan Derrfuss
Birte Forstmann
Hannes Ruge
Iring Koch
Nachshon Meiran
Orit Rubin
Markus Ullsperger
Thomas Knösche
D.Yves von Cramon
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Max Planck Institute for Human Cognitive and Brain Sciences
The fronto-lateral cortex
dorsolateral
ventrolateral
inferior-frontal junction (IFJ)
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Max Planck Institute for Human Cognitive and Brain Sciences
Neuronal correlates of task-switching
Dove et al. (2000)
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Max Planck Institute for Human Cognitive and Brain Sciences
Cognitive processes involved in task-switching
a) preparation related control processes
• task preparation reduces switch-costs
b) execution related control processes
• even with optimal preparation there are residual costs
Processes involved in task-switching
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Max Planck Institute for Human Cognitive and Brain Sciences
The task-cueing paradigm
cue taskpreparation
Cue-target interval (CTI)
By presenting a cue in advance to the task one can
separate cue-related and target related processes.
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Max Planck Institute for Human Cognitive and Brain Sciences
Separating task preparationfrom execution-related control
• A number between 20 and 40 (not 30) was displayed.
• Magnitude task: Is the number greater or smaller 30?
• Parity task: Is the number odd or even?
• A cue indicated which task to execute.
magnitude task parity task
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Max Planck Institute for Human Cognitive and Brain Sciences
Experimental paradigm
33 33
Fixation0-200 ms
Cue400-1600 ms
Target1600-2400 ms
Response
withpreparation
withoutpreparation
onlypreparation null
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Max Planck Institute for Human Cognitive and Brain Sciences
33
Demonstration of a trial
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Max Planck Institute for Human Cognitive and Brain Sciences
Behavioral resultsR
ea
cti
on
tim
e
(ms
)
750
800
850
900
950
1000
1050withoutpreparation
withpreparation
repeat switch
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Max Planck Institute for Human Cognitive and Brain Sciences
Cue-related activation
Brass & von Cramon (2002)
cueing effect (ms)
100 150 200 250 300 350 400
signal change (%)0,0
0,2
0,4
0,6
0,8
preSMAr=.57
r=.63IFJ
cueing effect (ms)
100 150 200 250 300 350 400
signal change (%)
-0,1
0,0
0,1
0,2
0,3
0,4
0,5
IFj r=.63
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Max Planck Institute for Human Cognitive and Brain Sciences
Conclusion
• The IFJ and the preSMA are involved in task preparation.
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Max Planck Institute for Human Cognitive and Brain Sciences
Open question
• Are these areas involved in the encoding of the cue or the
updating of the task representation?
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Max Planck Institute for Human Cognitive and Brain Sciences
Decomposing components of task preparation
• By assigning two cues to each task one can dissociate cue
encoding from task-set updating
= parity judgment= magnitude judgment
cue repetition
cue switch
meaning switch
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Max Planck Institute for Human Cognitive and Brain Sciences
Decomposing components of task preparation
• within-trial manipulation of cue-related processing
task
Processing related tocue 1
cue 1 cue 2
Processing related tocue 2
taskcue 1 cue 2
long CTI
short CTI
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Max Planck Institute for Human Cognitive and Brain Sciences
Experimental paradigm
33 33
Fixation0-200 ms
Cue 2 (100 ms)
Response
CCI=700
33
333333
Cue 1 (100 ms)
Cue 1 (100 ms)
Target
Target
CTI=60/700
CTI=60/700
Response
cuerepetion
cueswitch
meaningswitch
singlecue
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Max Planck Institute for Human Cognitive and Brain Sciences
33
Demonstration of a trial
32
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Max Planck Institute for Human Cognitive and Brain Sciences
Behavioral results
long CTIshort CTI
repe
titio
n
Cue-s
witc
h
Mea
ning
-
switc
h
repe
titio
n
Cue-s
witc
h
Mea
ning
-
switc
h
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Max Planck Institute for Human Cognitive and Brain Sciences
Meaning-switch versus cue-switch
z > 3.1
Brass & von Cramon (2004)
IFJ
Intra-parietal sulcus
Inferior frontal gyrus
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Max Planck Institute for Human Cognitive and Brain Sciences
Signal change analysis
cue-repetiton
cue-switch
meaning-switch
left IFJ
cue-repetiton
cue-switch
meaning-switch
IPS
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Max Planck Institute for Human Cognitive and Brain Sciences
Signal change analysis
0 1 2 3 4
signal change (%)
0,42
0,44
0,46
0,48
0,50
0,52
preSMA
cue-repetiton
cue-switch
meaning-switch
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Max Planck Institute for Human Cognitive and Brain Sciences
Who comes first?
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C
abstract task representation concrete task representation
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Max Planck Institute for Human Cognitive and Brain Sciences
Who comes first?
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C
w
Max Planck Institute for Human Cognitive and Brain Sciences
Who comes first?
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C
Brass, Ullsperger, Knösche & Phillips (in preparation)
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Max Planck Institute for Human Cognitive and Brain Sciences
Conclusions
• The IFJ and the IPS are related to the activation of task
representations.
• There is a hierachical order of prefrontal and parietal cortex
in task preparation.
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Max Planck Institute for Human Cognitive and Brain Sciences
Manipulating the association of cue and task
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C
• integrating information over time
• distinguishing relevant from irrelevant information
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Max Planck Institute for Human Cognitive and Brain Sciences
Manipulating the association of cue and task
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C
magnitude
parity
Task cues
switch
repeat
Transition cues
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Max Planck Institute for Human Cognitive and Brain Sciences
The paradigm
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
CTask Cue
7
Transition Cue
6
1
Task Cue
Transition Cue
9
Magnitude Task
ParityTask
ParityTask
ParityTask
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Max Planck Institute for Human Cognitive and Brain Sciences
Behavioral results
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C
0
200
400
600
800
1000
1200
1400
Repeat Switch
Reaction Time in ms
Transition Cue
Task Cue
0
2
4
6
8
10
Repeat Switch
Error Rates in %
Transition Cue
Task Cue
2A 2B
Forstmann, Brass, Koch & von Cramon (submitted)
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Max Planck Institute for Human Cognitive and Brain Sciences
fMRI results
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C
2A
5.13.1
2BFrontolateral Gradient
0
0,05
0,1
0,15
0,2
0,25
Mid-MFG IFJ
(-44, 23, 27) (-35, -4, 32)
% Signal Change
*
Frontomedian Gradient
0
0,05
0,1
0,15
0,2
0,25
BA 8 pre-SMA/SMA
(-5, 17, 50) (1, 5, 53)
% Signal Change
*
Forstmann, Brass & von Cramon (submitted)
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Max Planck Institute for Human Cognitive and Brain Sciences
The selection of task-relevant information
congruent incongruent neutral
red green xxxx
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Max Planck Institute for Human Cognitive and Brain Sciences
Cue dimensions
magnitudetask
no TaskParitytask
form dimension
color dimension
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Max Planck Institute for Human Cognitive and Brain Sciences
Cues
formdimension
colordimension
task A task B
congruent neutralincongruent congruent neutralincongruent
irrelevant
relevant
irrelevant
relevant
A AA
AB
B A NONO
NO NO
A AA B BB
BB B
A B
A B
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Max Planck Institute for Human Cognitive and Brain Sciences
7
Demonstration of a trial
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Max Planck Institute for Human Cognitive and Brain Sciences
Design
Instruction 1 warm up trial + 32 experimental trials + 4 null-events
Block
Block order
formcolor
formcolor
formcolor
formcolor
formcolor
formcolor
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Max Planck Institute for Human Cognitive and Brain Sciences
Behavioral results
Brass & von Cramon (submitted)
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Max Planck Institute for Human Cognitive and Brain Sciences
Possible contrasts
a) Incongruent/congruent (bivalent) versus neutral (univalent)
• selection of task-relevant context
b) Incongruent versus congruent
• selection of conflicting task representations
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Max Planck Institute for Human Cognitive and Brain Sciences
Brass & von Cramon (submitted)
neu con incon
neu con incon
Incongruent/congruent vs. neutral
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Max Planck Institute for Human Cognitive and Brain Sciences
Conclusions
• Cortical areas more anterior in the prefronal cortex come
into play, whenever the information in the environment does
not directly indicate the relevant task-set.
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Max Planck Institute for Human Cognitive and Brain Sciences
General conclusions
• The IFJ and the IPS play a crucial role in task preparation.
• Activation in the IFJ precedes activation in the IPS.
• Whenever the cue does not directly indicate which task to
execute, activation shifts anterior in the prefrontal cortex.
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Max Planck Institute for Human Cognitive and Brain Sciences
The IFJ at the junction of three cortical domains
pre
mo
tor
do
mai
n
premotor domain• task-rules are an abstraction from stimulus-repsonse rules
language
domain
language domain• task-rules are represented in an abstract language-like formatpre
fronta
l dom
ain
prefrontal domain• task-rules are required for high-order cognitive control
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Max Planck Institute for Human Cognitive and Brain Sciences
Neuronal correlates of task-switching
Dove et al. (2000)
If + left hand, if + right hand
Basis Taskfrequent
Critical Taskseldom
Response
w
Max Planck Institute for Human Cognitive and Brain Sciences
Neuronal correlates of task-switching
Dove et al. (2000)
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Max Planck Institute for Human Cognitive and Brain Sciences
Neuronal correlates of task-switching
Dove et al. (2000)
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Max Planck Institute for Human Cognitive and Brain Sciences
Fast versus slow responses in the long CTI
Brass & von Cramon (2002)
IFJ
CTI
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Max Planck Institute for Human Cognitive and Brain Sciences
Fast versus slow responses in the long CTI
Brass & von Cramon (2002)
IFJ
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Max Planck Institute for Human Cognitive and Brain Sciences
Cue-target versus cue-only
Brass & von Cramon (2002)
IFJ
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Max Planck Institute for Human Cognitive and Brain Sciences
(1) Task-switching
Participants have to alternate between different task-sets
(2) Stroop interference task
A relevant but non-dominant stimulus dimension has to be
enforced against a irrelevant but dominant stimulus dimension.
(3) Verbal n-back task
Information have to be coordinated in working memory.
Paradigms on cognitive control
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Max Planck Institute for Human Cognitive and Brain Sciences
Results of within-subject comparison
Overlap of activations in Stroop, task-switching and n-back
Derrfuss, Brass & von Cramon (submitted)
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Max Planck Institute for Human Cognitive and Brain Sciences
Who comes first?
-2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C -2.5+2.5µV0.400 .. 0.520 s
-0.20.20.40.60.8
-5.0-2.5 2.55.0
s
µV
FCz
-2.5 2.5
FCzcue switch, meaning repeat
cue switch, meaning switch
meaning switch - meaning repeat
difference waveERPA B
C
33
cueswitch
3333
meaningswitch
trigger
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Max Planck Institute for Human Cognitive and Brain Sciences
Signal change analysis
Brass & von Cramon (submitted)
magnitudetask
parity task
color form color form
inconconneu inconconneuinconconneu inconconneu
inconconneu inconconneu inconconneu inconconneu
magnitudetask
parity task