The primary objective of this study is to further validate theta/beta ratio (TBR) as a biomarker for PFC-mediated cognitive control by administering caffeine. We hypothesize that caffeine will up-regulate PFC-mediated cognitive control, and thereby…
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Condition
- Other condition
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Health condition
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Intervention
Outcome measures
Primary outcome
a) The change in performance (as measured with reaction times; RTs) on two
cognitive tasks (n-back task & switch task) after caffeine consumption,
relative to placebo consumption. We expect performance to improve (RTs to
decrease) after caffeine consumption.
b) The change in the ratio between EEG measured theta and beta oscillations
after caffeine consumption (relative to placebo consumption). We expect
theta/beta ratio to decrease after caffeine consumption, thereby mediating the
effects of caffeine on cognitive performance.
Secondary outcome
a) The moderating effects of baseline dopamine activity (measured with baseline
spontaneous eye blink rates and theta/beta ratio) on the effects of caffeine on
cognition.
b) The possible confounding effects of self-reported ADHD symptoms, sleepiness,
and anxiety on the effects of caffeine on cognition.
Background summary
PFC-mediated cognitive control (which includes many processes such as
attentional inhibition and emotion regulation) is thought to play an important
role in cognitive functioning, allowing humans to exert top-down, goal-driven
control over stimulus-driven, automatic processes. Previous EEG studies
examining cognitive control have identified a potential biomarker for
PFC-mediated cognitive control. These studies have found that the ratio between
EEG-measured theta and beta brain oscillations is elevated in children with
ADHD (a group of children who generally experience poor cognitive control), and
in unselected adults with poor attentional control. This theta/beta ratio (TBR)
is thought to reflect the extent to which prefrontal brain activity exhibits
regulatory control over more posterior and subcortical brain areas. In the
present study we propose a new method to further validate TBR as a biomarker
for cognitive control, by administering caffeine to participants. Caffeine
consumption improves cognitive control, which should lead to a decrease in TBR.
In addition, the neurotransmitter dopamine plays an important role in
PFC-mediated cognitive functioning, and may therefore moderate the relationship
between caffeine consumption and cognitive control. In the present study, we
will address this possible moderating role of dopamine by measuring
participants* baseline theta/beta ratio, which is thought to reflect prefrontal
dopamine activity, and spontaneous eye-blink rate, which is thought to measure
central dopamine activity. Finally, in this study we will explore several other
possible confounding factors in the relationship between caffeine consumption
and cognitive control, including anxiety, sleepiness, and ADHD symptoms.
Study objective
The primary objective of this study is to further validate theta/beta ratio
(TBR) as a biomarker for PFC-mediated cognitive control by administering
caffeine. We hypothesize that caffeine will up-regulate PFC-mediated cognitive
control, and thereby decrease TBR. The secondary objective of this study is to
examine likely non-linear relations between caffeine, PFC-mediated cognitive
functioning, and dopamine activity, by taking into account baseline theta/beta
ratio and spontaneous eye-blink rates as moderating factors on the influence of
caffeine on cognitive control. The tertiary objective of this study is to
examine the possible confounding effects of sleepiness, anxiety, and ADHD
symptoms in the effects of caffeine on TBR and cognitive control.
Study design
A double-blind, randomized, placebo-controlled, cross-over trial.
Intervention
Participants will visit the lab three times. In two lab sessions, separated by
one week, participants will orally consume one capsule containing 200mg of pure
caffeine (a similar amount of caffeine is found in about 2 cups of coffee) and
one capsule containing a placebo filler substance (randomized and double-blind
administration).
Study burden and risks
No risks are involved with participation in this study. The only burden for
participants is investment of time and effort, for which they will be
reimbursed. After caffeine consumption, participants may experience a temporary
increase in effects associated with caffeine consumption (e.g. arousal,
cognitive performance). No (other) benefits are expected to be experienced by
the participants.
Wassenaarseweg 52
Leiden 2300RB
NL
Wassenaarseweg 52
Leiden 2300RB
NL
Listed location countries
Age
Inclusion criteria
- Female
- Age 18-25 years
- Consuming less than 100mg of caffeine (about one cup of coffee) per day on average
- Fluent in Dutch language
Exclusion criteria
- Severe physical or psychological morbidity that would adversely affect participation
- Habitual smoking
- Use of psychopharmaceutics
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL55346.058.15 |