CeRCA (CNRS-UMR 7295), Faculty of Sport Sciences, University of Poitiers Poitiers, France.
Movement to Health (M2H), Montpellier-1 University, Euromov, Montpellier France.
Front Aging Neurosci. 2014 Oct 8;6:272. doi: 10.3389/fnagi.2014.00272. eCollection 2014.
Cardiorespiratory fitness has been shown to protect and enhance cognitive and brain functions, but little is known about the cortical mechanisms that underlie these changes in older adults. In this study, functional near infrared spectroscopy (fNIRS) was used to investigate variations in oxyhemoglobin [HbO2] and in deoxyhemoglobin [HHb] in the dorsolateral prefrontal cortex (DLPFC) during the performance of an executive control task in older women with different levels of cardiorespiratory fitness (VO2max). Thirty-four women aged 60-77 years were classified as high-fit and low-fit based on VO2max measures. They all performed a control counting (CNT) task and the Random Number Generation (RNG) task at two different paces (1 number/1 s and 1 number/1.5 s), allowing to manipulate task difficulty, while hemodynamic responses in the bilateral DLPFCs were recorded using continuous-wave NIRS. The behavioral data revealed that the high-fit women showed significantly better performance on the RNG tasks compared with the low-fit women. The high-fit women showed significant increases in [HbO2] responses in both left and right DLPFCs during the RNG task, while the low-fit women showed significantly less activation in the right DLPFC compared with the right DLPFC of the high-fit women and compared with their own left DLPFC. At the level of the whole sample, increases in the [HbO2] responses in the right DLPFC were found to mediate in part the relationship between VO2max level and executive performance during the RNG task at 1.5 s but not at 1 s. These results provide support for the cardiorespiratory fitness hypothesis and suggest that higher levels of aerobic fitness in older women are related to increased cerebral oxygen supply to the DLPFC, sustaining better cognitive performance.
心肺适能已被证明可以保护和增强认知和大脑功能，但对于老年人中这些变化的皮质机制知之甚少。在这项研究中，使用功能近红外光谱（fNIRS）来研究在执行控制任务期间，不同心肺适能（VO2max）水平的老年女性背外侧前额叶皮层（DLPFC）中的氧合血红蛋白 [HbO2] 和脱氧血红蛋白 [HHb] 的变化。根据 VO2max 测量值，34 名年龄在 60-77 岁的女性被分为高适能和低适能组。他们都在两种不同的节奏（1 个数字/1 秒和 1 个数字/1.5 秒）下执行控制计数（CNT）任务和随机数生成（RNG）任务，以操纵任务难度，同时使用连续波 NIRS 记录双侧 DLPFC 的血液动力学反应。行为数据显示，高适能女性在 RNG 任务中的表现明显优于低适能女性。高适能女性在 RNG 任务中左右 DLPFC 的 [HbO2] 反应均显著增加，而低适能女性右侧 DLPFC 的激活明显低于高适能女性的右侧 DLPFC 和其自身的左侧 DLPFC。在整个样本水平上，发现右侧 DLPFC 的 [HbO2] 反应增加部分介导了 VO2max 水平与 RNG 任务 1.5 秒时执行表现之间的关系，但在 1 秒时则没有。这些结果为心肺适能假说提供了支持，并表明老年女性更高水平的有氧适能与 DLPFC 的大脑氧供应增加有关，从而维持更好的认知表现。
