The Effects of a Single Administration of a Moderate Dose of Caffeine on Cognitive Control and Spontaneous EEG Theta/Beta Ratio
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 41
- 试验地点
- 1
- 主要终点
- Attentional focus (RT)
研究概览
简要总结
Cognitive control driven by the prefrontal cortex (PFC) of the brain is thought to be important for goal-directed control over stimulus-driven processes. EEG-measured spontaneous theta/beta ratio (TBR) may potentially be used as an electrophysiological marker for this PFC-mediated cognitive control. In the present study the investigators further examine TBR as an electrophysiological marker for cognitive control, by administering caffeine to forty healthy female participants. After a first training session, participants will visit the lab twice in separate weeks, during which they will orally consume one capsule containing 200mg of caffeine, and one capsule containing a placebo substance (double-blind and random order of administration). EEG will be measured before and after capsule consumption, and cognitive control tasks will be administered after capsule consumption. Generally, the investigators expect that caffeine will decrease TBR and thereby increase cognitive control. Additionally, the investigators expect that individual differences in baseline frontal (reflected by TBR) and central dopaminergic (reflected by spontaneously-measured eye-blink rates; EBR) activity will moderate the relationship between caffeine and cognitive control. Furthermore, the effects of caffeine on specifically hypervigilance for threatening distractors (taking into account a possible moderating role of trait anxiety) were examined as a separate research question.
详细描述
BACKGROUND AND RESEARCH AIMS
Cognitive control is an essential part of cognitive functioning, allowing top-down, goal-driven control over stimulus-driven, automatic processes. The prefrontal cortex (PFC) of the brain likely plays an important role in many aspects of cognitive control, including goal-driven attention, working memory, and emotion regulation. Previous EEG studies examining cognitive control have identified a potential electrophysiological marker 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 (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, which has made this measure useful in the diagnosis and treatment of disorders related to poor cognitive control such as ADHD.
In the present study, the investigators propose a new method to further validate TBR as an electrophysiological marker for cognitive control, by administering caffeine to participants. Caffeine is widely-known to improve various aspects of cognitive control, which would be expected to go alongside a decrease in TBR.
Importantly, cognitive control benefits from both the maintenance of task-relevant representations and the flexible updating of these representations. These cognitive control functions may rely on somewhat different areas of the brain. Namely, whereas maintenance of task-relevant representations may be more dependent on PFC functioning, the flexible updating of these representations may rely more on dopaminergic activity in the striatum. Theta/beta ratio as a marker of PFC activity may thus specifically reflect task-relevant maintenance of information, and contrasting this EEG measure to a measure of striatal dopamine activity may shed more light on the nature of TBR. In the present study, the investigators will do so by measuring spontaneous eye-blink rates (EBR), which have shown to be sensitive to dopaminergic striatal activity.
The first aim of the present study will be to further validate theta/beta ratio (TBR) as an electrophysiological marker for PFC-mediated cognitive control by administering caffeine to healthy participants. The investigators expect that (1a) theta/beta ratio will be inversely related to cognitive control performance (attentional focus, attentional shift, working memory; measured with TACT and N-back; possibly mainly related to TACT focus performance), (1b) caffeine will increase cognitive control performance, (1c) caffeine will decrease theta/beta ratio, and that (1d) these beneficial effects of caffeine on cognitive performance will be mediated by this decrease in theta/beta ratio.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 18 Years 至 26 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Inclusion and
排除标准
- •will be assessed via self-report.
- •Inclusion Criteria:
- •Age 18-26 years
- •Consuming less than 100mg of caffeine (about one cup of coffee) per day on average (evaluated using pre-defined caffeine contents, e.g.: coffee: 85mg/cup; cappuccino: 100mg/cup; tea: 40mg/cup; cola: 18mg/cup; energy drink: 80mg/can)
- •Fluent in Dutch language
- •Exclusion Criteria:
- •Severe physical or psychological morbidity that would adversely affect participation
- •Habitual smoking
- •Use of psychopharmaceuticals
研究组 & 干预措施
Caffeine first, placebo second
Caffeine consumption during session 1, placebo consumption during session 2 (after baseline session "0").
干预措施: Placebo (Other)
Placebo first, caffeine second
Placebo consumption during session 1, caffeine consumption during session 2 (after baseline session "0").
干预措施: Placebo (Other)
Placebo first, caffeine second
Placebo consumption during session 1, caffeine consumption during session 2 (after baseline session "0").
干预措施: Caffeine (200mg) (Dietary Supplement)
Caffeine first, placebo second
Caffeine consumption during session 1, placebo consumption during session 2 (after baseline session "0").
干预措施: Caffeine (200mg) (Dietary Supplement)
结局指标
主要结局
Attentional focus (RT)
时间窗: Approx. 45 min after capsule consumption
TACT focus RTs on incongruent v congruent (correct) trials.
Attentional shift (RT)
时间窗: Approx. 45 min after capsule consumption
TACT shift RTs on post-shift trials compared to pre-shift (correct) trials.
Working memory (ACC)
时间窗: Approx. 60 min after capsule consumption
N-Back accuracy (% correct) in the 1-back and 3-back conditions.
Emotional interference (RT)
时间窗: Approx. 70 min after capsule consumption
Emotional Stroop Task RTs for neutral, positive, and negative (correct) trials.
Working memory (RT)
时间窗: Approx. 60 min after capsule consumption
N-Back RTs on correct trials in the 1-back and 3-back conditions.
EEG theta/beta ratio
时间窗: Baseline
For moderation analyses, baseline-measured spontaneous EEG theta/beta ratio.
Spontaneous eye-blink rates
时间窗: Baseline
For moderation analyses, baseline-measured spontaneous eye-blink rates.
Trait anxiety
时间窗: Baseline
Self-reported trait anxiety (STAI-t)
EEG theta/beta ratio
时间窗: Approx. 30 min after capsule consumption
For mediation analyses, change in EEG theta/beta ratio after caffeine consumption relative to placebo consumption.
次要结局
- Attentional focus (ACC)(Approx. 45 min after capsule consumption)
- Attentional shift (ACC)(Approx. 45 min after capsule consumption)
研究者
PeterPutman
Associate Professor
Leiden University Medical Center