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Chapter 2
compared with the previous trial, or switched. Finally, a reward cue at the start of each trial
indicated whether €0.01 or €0.15 (or sometimes €0.10;
chapter 5
) could be earned after a
correct and sufficiently fast response. Immediately following the response, feedback was
given (e.g., “correct! 1 cent”).
Responses (both behaviourally and neurally) on this task can be used to assess switching
(by comparing switch to repeat trials), reward anticipation (by comparing high with low
reward trials) and their interaction (i.e. low reward (switch – repeat) – high reward (switch
– repeat). In addition, in chapter 7 this paradigm is used to assess the integration between
reward, task switching and motor switching.
This paradigm is used throughout this thesis to assess the effects of a dopamine receptor
agonist (
chapter 3
) on behaviour and to assess differences in neural signalling (
box 2.4
)
between patients with ADHD and the effects of methylphenidate (
box 2.2;
chapter 4
).
Subsequently, it was used to investigatewhether performance on this task changes across the
life span (
chapter 5
). In
chapter 6
I present a version of this paradigm designed for rodents
to assess the causal role for the striatum (
box 2.5
)
in successful motivation-cognition
integration. Finally, in
chapter 7
I used non-invasive brain stimulation (
box 2.5
)
in human
subjects to perturb activity in the neural circuitry involved in reward processing to gain
insight in the neural mechanism underlying the reward, cognition, action integration.
reward cue
task cue
target
feedback
response
word
15 cent
TRIAL 4
high reward
task switch
response switch
le
le
right
correct!
15 cent
incorrect!
0 cent
TRIAL 3
low reward
task repeat
response switch
arrow
le
1 cent
le
right
correct!
1 cent
incorrect!
0 cent
TRIAL 2
low reward
task switch
response repeat
1 cent
arrow
right
le
right
correct!
1 cent
incorrect!
0 cent
TRIAL 1
15 cent
word
le
correct!
15 cent
le
incorrect!
0 cent
right