Barry Robert J, Clarke Adam R, Johnstone Stuart J, Rushby Jacqueline A
Brain & Behaviour Research Institute and School of Psychology, University of Wollongong, Wollongong, NSW 2522, Australia.
Biol Psychol. 2008 Mar;77(3):304-16. doi: 10.1016/j.biopsycho.2007.11.002. Epub 2007 Nov 13.
The timing of caffeine effects on arousal levels was examined. From previous work in our laboratory, an increase in skin conductance level (SCL) was used as the marker of arousal increase, and we sought to identify the timing of this and related effects following caffeine ingestion. A single oral dose of caffeine (250 mg) was used in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eyes-closed resting electroencephalogram (EEG) and autonomic data (SCL, heart rate, respiration rate, and systolic and diastolic blood pressure) during 2 min epochs that commenced every 4 min after ingestion, were analysed. The SCL placebo data were used to identify potential arousal measures prior to examining caffeine effects. Caffeine was associated with increased SCL, increased respiratory rate and a global reduction in alpha power. There were no significant cardiovascular effects of caffeine-induced arousal. These caffeine results are consistent with our recent electrodermal and EEG studies of arousal, and confirm the potential use of caffeine as a simple means of experimentally modifying arousal levels without task-related confounds.
研究了咖啡因对唤醒水平影响的时间。根据我们实验室之前的研究，皮肤电导率水平（SCL）的升高被用作唤醒增加的指标，我们试图确定摄入咖啡因后这种影响及相关效应的时间。在一项随机双盲安慰剂对照重复测量交叉研究中，使用了单剂量口服咖啡因（250毫克）。对摄入咖啡因后每4分钟开始的2分钟时段内的闭眼静息脑电图（EEG）和自主神经数据（SCL、心率、呼吸频率以及收缩压和舒张压）进行了分析。在检查咖啡因效应之前，使用SCL安慰剂数据来确定潜在的唤醒指标。咖啡因与SCL升高、呼吸频率增加以及α波功率整体降低有关。咖啡因引起的唤醒对心血管没有显著影响。这些咖啡因研究结果与我们最近关于唤醒的皮肤电反应和EEG研究一致，并证实了咖啡因作为一种在无任务相关混淆因素情况下实验性改变唤醒水平的简单方法的潜在用途。
