Lorist M M, Snel J, Mulder G, Kok A
Department of Psychonomics, University of Amsterdam, The Netherlands.
Electroencephalogr Clin Neurophysiol. 1995 Sep;96(5):453-67. doi: 10.1016/0168-5597(95)00069-5.
Structural and energetic processes in information processing were studied in young and elderly subjects. A visually focussed selective search task was used, in which subjects had to select relevant information, followed by controlled memory search processes to locate a target item. Caffeine was used to manipulate the energetic state of the subjects. During task performance event-related potentials (ERPs) and reaction time (RT) were recorded. Subjects were 15 young and 15 elderly healthy, non-smoking, moderate caffeine consumers (250-600 mg/day). Before the experimental sessions they abstained from caffeine for > or = 12 h. In the experiment subjects received 250 mg caffeine or placebo dissolved in decaffeinated coffee. RT data seem to indicate that aging effects are at least partly due to a shift in the speed-accuracy trade-off. ERP results provide evidence for decreased levels of energy resources in the elderly. The identification of relevant information and stimulus evaluation processes were delayed in the elderly, suggesting an additional effect of aging on structural processes. Caffeine improved performance and increased the amplitude of the N1, N2b, and P3b, in both young and old subjects. These results suggest that caffeine makes more energy resources available for task performance. The effects of aging on P3b latency were counteracted by caffeine. Other caffeine effects did not differ significantly between young and elderly subjects.
对年轻人和老年人信息处理中的结构和能量过程进行了研究。采用了视觉聚焦的选择性搜索任务，在该任务中，受试者必须选择相关信息，随后进行受控的记忆搜索过程以定位目标项目。使用咖啡因来操纵受试者的能量状态。在任务执行期间，记录事件相关电位（ERP）和反应时间（RT）。受试者为15名年轻和15名老年健康、不吸烟、适度饮用咖啡因（每天250 - 600毫克）的人。在实验环节之前，他们停止摄入咖啡因至少12小时。在实验中，受试者饮用溶解有250毫克咖啡因或安慰剂的脱咖啡因咖啡。RT数据似乎表明，衰老效应至少部分是由于速度 - 准确性权衡的转变。ERP结果为老年人能量资源水平降低提供了证据。老年人识别相关信息和刺激评估过程有所延迟，这表明衰老对结构过程有额外影响。咖啡因改善了年轻和老年受试者的表现，并增加了N1、N2b和P3b的波幅。这些结果表明，咖啡因使更多能量资源可用于任务执行。咖啡因抵消了衰老对P3b潜伏期的影响。年轻和老年受试者之间的其他咖啡因效应没有显著差异。
