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39
General introduction
Box 2.3 | Cued task-switching paradigm with a reward manipulation
Subjects were presented with response-incongruent arrow-word combinations (targets),
to which they had to respond by pressing a left or right button. There were two possible
targets: a left-pointing arrow with the word ‘right’ in it (e.g. trial 2), and a right-pointing
arrow with the word ‘left’ in it. A task cue preceding the target indicated according to
which task (arrow or word) the subject had to respond on the current trial. Compared
with the previous trial, the task could either switch (e.g. from word to arrow or vice
versa) or remain the same (i.e. repeat). Switch and repeat trials occurred in random order.
In addition to such task switches, the paradigm allows us to look at response switches
(
chapter 7
), i.e. whether the correct response (left or right button), remained the same
DAT expression
Study
Sample
N: total
(age)
N:
9/9; 9/10;
10/10
SPECT
Ligand
ROI
9R+ > 10/10
van de
Giessen
2009
Healthy
79
(18-35)
5;27;45
β-CIT
9R/9R vs. 10/10
sign in P
9R/10R vs. 10/10
in striatum, CN
and P
9R+ > 10/10
van Dyck
2005
Healthy
96
(18-88)
5;36;53
β-CIT
Both in CN and P
9R+ > 10/10
Jacobsen
2000
Healthy
27
(37 + 9.3)
2;7;18
β-CIT
Striatum
9/10 < 10/10
Heinz
2000
AA and
H
14 AA
(37 + 7)
11 H
(34 + 11)
0;10;15
β-CIT
P (CN is not
significant)
9/10 &
10/11<10/10
Cheon
2005
ADHD
11
(9.82 + 1.33)
4x 9/10,
10/11;
7x 10/10
[
123
I]IPT
BG
No effect
Martinez
2001
H and
SZ
31 H (~40.5)
29 SZ (~39)
23x 9/9
9/10, 9/11;
36x 10/10
β-CIT
No effects
No effect
Lafuente
2007
SZ
62 SZ (~30)
5;30;25
[
123
I] FP-CIT
No effects (CN,
aP, mP, pP)
No effect
Lynch
2003
H
and
PD
66 H: 46
(18-83)
95 PD: 60.8
(37-84)
14;68;74;
other:7
99
Tc-
TRODAT-1
No effects
SZ = schizophrenia patients, H = healthy subjects; AA = abstinent alcoholics; PD = Parkinson’s disease; ADHD = attention
deficit hyperactivity disorder (Korean children); CN = caudate nucleus; P = putamen (aP, mP and pP refer to anterior,
medial or posterior putamen); β-CIT =
123
I-(2- β -carbomethoxy-3-β(4-iodophenyl)-tropane; [
123
I]IPT = I-123-N-(3-
iodopropen-2-yl)-2h-carbomethoxy-3beta-(4-chlorophenyl)tropane