Qin Shuo, Basak Chandramallika
Center for Vital Longevity, The University of Texas at Dallas, Dallas, TX, United States.
Front Hum Neurosci. 2020 Sep 9;14:561877. doi: 10.3389/fnhum.2020.561877. eCollection 2020.
Not only are the effects of cardiovascular risk factors such as high blood pressure and low fitness on executive functions and brain activations in older adults scarcely investigated, no fMRI study has investigated the combined effects of multiple risk factors on brain activations in older adults. This fMRI study examined the independent and combined effects of two cardiovascular risk factors, arterial plasticity, and physical fitness, on brain activations during task-switching in older adults. The effects of these two risk factors on age-related differences in activation between older and younger adults were also examined. Independently, low physical fitness and low arterial plasticity were related to reduced suppressions of occipital brain regions. The combined effects of these two risks on occipital regions were greater than the independent effects of either risk factor. Age-related overactivations in frontal cortex were observed in low fitness older adults. Brain-behavior correlation indicates that these frontal overactivations are maladaptive to older adults' task performance. It is possible that the resulting effects of cardiovascular risks on the aging brain, especially the maladaptive overactivations of frontal brain regions by high risk older adults, contribute to often found posterior-anterior shift in aging (PASA) brain activations. Furthermore, observed age-related differences in brain activations during task-switching can be partially attributed to individual differences in cardiovascular risks among older adults.
高血压和低体能等心血管危险因素对老年人执行功能和大脑激活的影响几乎未被研究，也没有功能磁共振成像（fMRI）研究探讨多种危险因素对老年人大脑激活的综合影响。这项fMRI研究考察了两个心血管危险因素——动脉可塑性和体能，对老年人任务转换期间大脑激活的独立及综合影响。还考察了这两个危险因素对老年人与年轻人激活方面年龄相关差异的影响。单独来看，低体能和低动脉可塑性与枕叶脑区抑制作用减弱有关。这两个危险因素对枕叶区域的综合影响大于任一危险因素的单独影响。在低体能的老年人中观察到额叶皮层与年龄相关的过度激活。脑-行为相关性表明，这些额叶过度激活对老年人的任务表现具有不良适应性。心血管危险因素对衰老大脑产生的影响，尤其是高风险老年人额叶脑区的不良适应性过度激活，可能导致衰老过程中常见的脑激活后-前移位（PASA）。此外，在任务转换期间观察到的与年龄相关的大脑激活差异，部分可归因于老年人心血管危险因素的个体差异。
