Heilbronner Urs, Hinrichs Hermann, Heinze Hans-Jochen, Zaehle Tino
DZNE, German Center for Neurodegenerative Diseases, Otto-von-Guericke University, Magdeburg, Germany.
Institute of Psychiatric Phenomics and Genomics, Ludwig-Maximilians-University, Munich, Germany.
BMC Res Notes. 2015 Oct 1;8:520. doi: 10.1186/s13104-015-1491-3.
Caffeine is a widely used stimulant with potentially beneficial effects on cognition as well as vasoconstrictive properties. In functional magnetic imaging research, caffeine has gained attention as a potential enhancer of the blood oxygenation level-dependent (BOLD) response. In order to clarify changes of oxy- and deoxyhemoglobin (HbO and HbR) induced by caffeine during a cognitive task, we investigated a working memory (WM) paradigm (visual 2-back) using near-infrared spectroscopy (NIRS).
Behaviorally, caffeine had no effect on the WM performance but influenced reaction times in the 0-back condition. NIRS data demonstrate caffeine-dependent alterations of the course of the hemodynamic response. The intake of 200 mg caffeine caused a significant decrease of the HbO response between 20 and 40 s after the onset of a 2-back task in the bilateral inferior frontal cortex (IFC). In parallel, the HbR response of the left IFC was significantly increased due to caffeine intake.
In line with previous results, we did not detect an effect of caffeine on most aspects of behavior. Effects of caffeine on brain vasculature were detected as general reduction of HbO. Neuronal effects of caffeine are reflected in an increased concentration of HbR in the left hemisphere when performing a verbal memory task and suggest influences on metabolism.
咖啡因是一种广泛使用的兴奋剂，对认知有潜在的有益影响，同时具有血管收缩特性。在功能磁共振成像研究中，咖啡因作为血氧水平依赖（BOLD）反应的潜在增强剂受到关注。为了阐明咖啡因在认知任务期间引起的氧合血红蛋白和脱氧血红蛋白（HbO和HbR）的变化，我们使用近红外光谱（NIRS）研究了工作记忆（WM）范式（视觉2-back）。
在行为上，咖啡因对WM表现没有影响，但影响了0-back条件下的反应时间。NIRS数据表明咖啡因依赖的血流动力学反应过程的改变。摄入200毫克咖啡因导致双侧额下回（IFC）在2-back任务开始后20至40秒之间HbO反应显著降低。同时，由于摄入咖啡因，左侧IFC的HbR反应显著增加。
与先前的结果一致，我们未检测到咖啡因对行为的大多数方面有影响。咖啡因对脑血管的影响表现为HbO的普遍降低。咖啡因的神经元效应体现在执行言语记忆任务时左半球HbR浓度增加，提示对代谢有影响。
