Schroeter Matthias L, Zysset Stefan, Kruggel Frithjof, von Cramon D Yves
Max-Planck-Institute of Cognitive Neuroscience, Stephanstrasse 1A, 04103 Leipzig, Germany.
Neuroimage. 2003 Jul;19(3):555-64. doi: 10.1016/s1053-8119(03)00155-1.
Aging reduces cerebral blood flow in association cortices during rest. However, the influence of age on functional brain activation is still controversial. The aim of our study was to examine age dependency of brain activation in primary and association cortices. Therefore, changes in the concentration of oxy- and deoxyhemoglobin as well as changes in the redox state of cytochrome-c-oxidase (Cyt-Ox) were measured by functional near-infrared spectroscopy (fNIRS) in the lateral prefrontal and motor cortices during an event-related Stroop interference task. Fourteen young (23.9 +/- 3.1 years old) and 14 elderly subjects (65.1 +/- 3.1) participated in the study. Data revealed two effects of aging on brain activation: (1) Elderly and young subjects used the lateral prefrontal cortex to cope with interference during the Stroop task. In young subjects, the vascular response was higher during incongruent than neutral trials in the entire examined lateral prefrontal cortex. However, in the elderly, all lateral prefrontal regions showed a hemodynamic response but not necessarily a specific interference effect. (2) The hemodynamic response was reduced in elderly subjects in the lateral prefrontal association cortex, but obviously not in the motor cortex. We propose that calculating effect sizes is the only reliable approach to analyze age-related effects in fNIRS studies, because they are independent from the assumed differential pathlength factor. In summary, our findings suggest that aging decreases the hemodynamic response in the frontal association cortex during functional activation, omitting the primary motor cortex.
衰老会在静息状态下减少联合皮质的脑血流量。然而，年龄对脑功能激活的影响仍存在争议。我们研究的目的是检验初级皮质和联合皮质中脑激活的年龄依赖性。因此，在一项事件相关的Stroop干扰任务中，通过功能近红外光谱（fNIRS）测量了外侧前额叶皮质和运动皮质中氧合血红蛋白和脱氧血红蛋白浓度的变化以及细胞色素c氧化酶（Cyt-Ox）氧化还原状态的变化。14名年轻受试者（23.9±3.1岁）和14名老年受试者（65.1±3.1岁）参与了该研究。数据揭示了衰老对脑激活的两种影响：（1）老年和年轻受试者在Stroop任务中均利用外侧前额叶皮质来应对干扰。在年轻受试者中，在整个被检查的外侧前额叶皮质中，不一致试验期间的血管反应高于中性试验。然而，在老年人中，所有外侧前额叶区域均显示出血流动力学反应，但不一定有特定的干扰效应。（2）老年受试者外侧前额叶联合皮质中的血流动力学反应降低，但运动皮质中明显没有。我们认为，计算效应量是分析fNIRS研究中与年龄相关效应的唯一可靠方法，因为它们不受假定的差分程长因子的影响。总之，我们的研究结果表明，衰老会在功能激活期间降低额叶联合皮质的血流动力学反应，而初级运动皮质不受影响。
