The intake of caffeine and the prospect of reward have both been associated with increased arousal, enhanced attention, and improved behavioral performance on cognitive tasks, but how they interact to exert these effects is not well understood. To investigate this question, we had participants engage in a 2-session cued-reward cognitive task while recording their electrical brain activity using scalp electroencephalography. The cue indicated whether monetary reward could be received for fast and accurate responses to a color–word Stroop stimulus that followed. Before each session, participants ingested decaffeinated coffee with either caffeine (3-mg/kg bodyweight) or placebo (3-mg/kg bodyweight lactose). The behavioral results showed that both caffeine and reward-prospect improved response accuracy and speed. In the brain, reward-prospect resulted in an enlarged contingent negative variation (CNV) and reduced posterior alpha power (indicating increased cortical activity) before stimulus presentation, both neural markers for preparatory attention. Moreover, the CNV enhancement for reward-prospect trials was considerably more pronounced in the caffeine condition as compared to the placebo condition. These interactive neural enhancements because of caffeine and reward-prospect were mainly visible in preparatory attention activity triggered by the cue (CNV). In addition, some interactive neural enhancements in the processing of the Stroop target stimulus that followed were also observed. The results suggest that caffeine facilitates the neural processes underlying attentional preparation and stimulus processing, especially for task-relevant information.

咖啡因的摄入和奖励的前景都与提高唤醒、增强注意力和改善认知任务的行为表现有关，但它们如何相互作用以发挥这些影响尚不清楚。为了调查这个问题，我们让参与者在使用头皮脑电图记录他们的脑电活动的同时，参与了 2 个会话的提示奖励认知任务。提示表明是否可以通过对随后的颜色词 Stroop 刺激做出快速准确的反应来获得金钱奖励。在每次会议之前，参与者摄入含咖啡因（3 毫克/公斤体重）或安慰剂（3 毫克/公斤体重乳糖）的脱咖啡因咖啡。行为结果表明，咖啡因和奖励前景都提高了反应的准确性和速度。在大脑中，奖励前景导致在刺激呈现之前扩大的偶然负变异 (CNV) 和降低的后α 功率（表明皮质活动增加），这两种神经标志物都是准备注意的神经标志物。此外，与安慰剂条件相比，在咖啡因条件下，奖励前景试验的 CNV 增强要明显得多。由于咖啡因和奖励前景而导致的这些交互式神经增强主要在由提示 (CNV) 触发的预备性注意活动中可见。此外，还观察到了在处理随后的 Stroop 目标刺激时的一些交互式神经增强。结果表明，咖啡因促进了注意力准备和刺激处理的神经过程，尤其是与任务相关的信息。