Université du Québec à Montréal, Case postale 8888, succursale, Centre-Ville, Montréal, QC, H3C 3P8, Canada.
Behav Brain Res. 2012 Jun 15;232(1):137-47. doi: 10.1016/j.bbr.2012.03.039. Epub 2012 Apr 1.
Glucose enhancing effects in older adults have mostly been observed for episodic memory, but have recently been found for attentional control performance. Yet, brain activation patterns underlying these effects are still unknown.
The present study examined the acute effects of glucose ingestion on prefrontal brain activation during the execution of a divided attention task in fasting non-diabetic older adults.
Twenty older adults (60 years and older) took part in the study that included two experimental sessions. After an overnight fast, participants received either a glucose drink (50 g) or a placebo (saccharin) drink, following which they completed a dual-task. During task execution, prefrontal activation was recorded with functional near-infrared spectroscopy (fNIRS). A repeated-measures design was used such that each participant served as his or her own control. The two experimental sessions were counterbalanced among participants and were performed two weeks apart.
When participants were in the glucose condition, they showed similar dual-task costs for both tasks, whereas in the placebo condition they prioritized one task over the other, with a significantly larger dual-task cost for the non-prioritized task (p<0.01). Differential brain activation was also observed in right ventral-lateral prefrontal regions for oxygenated hemoglobin and deoxygenated hemoglobin, with more activation apparent in the glucose condition (p<0.05). Furthermore, behavioral and activation data were influenced by individual differences in glucose regulation.
Glucose ingestion appears to momentarily enhance fasting seniors' capacity to coordinate more equally two concurrent tasks and this is reflected in brain activation patterns.
在老年人中，葡萄糖增强效应主要在情景记忆中观察到，但最近在注意力控制表现中也发现了这种效应。然而，这些效应背后的大脑激活模式仍然未知。
本研究在禁食非糖尿病老年人中，检查了葡萄糖摄入对执行分散注意任务时前额叶大脑激活的急性影响。
20 名老年人（60 岁及以上）参加了这项研究，该研究包括两个实验阶段。在一夜禁食后，参与者接受了葡萄糖饮料（50 克）或安慰剂（糖精）饮料，之后他们完成了一项双重任务。在任务执行过程中，使用功能近红外光谱（fNIRS）记录前额叶激活。采用重复测量设计，每个参与者都作为自己的对照。两个实验阶段在参与者之间平衡，并在两周内进行。
当参与者处于葡萄糖状态时，他们在两个任务上表现出相似的双重任务成本，而在安慰剂状态下，他们将一个任务优先于另一个任务，非优先任务的双重任务成本明显更大（p<0.01）。对于含氧血红蛋白和去氧血红蛋白，右侧腹外侧前额叶区域也观察到了不同的大脑激活，葡萄糖状态下的激活更为明显（p<0.05）。此外，行为和激活数据受到葡萄糖调节个体差异的影响。
葡萄糖摄入似乎暂时增强了禁食老年人同等协调两个并发任务的能力，这反映在大脑激活模式中。
