Center for Vital Longevity, University of Texas at Dallas, United States.
Center for Vital Longevity, University of Texas at Dallas, United States; Department of Psychology, School of Behavioral and Brain Sciences, University of Texas at Dallas, United States.
Neuropsychologia. 2022 Jul 29;172:108269. doi: 10.1016/j.neuropsychologia.2022.108269. Epub 2022 May 17.
Increases in cardiovascular risks such as high blood pressure and low physical fitness have been independently associated with altered default mode network (DMN) activation patterns in healthy aging. However, cardiovascular risk is a multidimensional health problem. Therefore, we need to investigate multiple cardiovascular risk factors and their contributions to cognition and DMN activations in older adults, which has not yet been done. The current fMRI study examined contributions of two common modifiable cardiovascular risk factors (arterial stiffness and physical fitness) on DMN activations involved during random n-back, a task of executive functioning and working memory, in older adults. The results show that high cardiovascular risk of either increased arterial stiffness or decreased fitness independently contributed to worse task performance and reduced deactivations in two DMN regions: the anterior and posterior cingulate cortices. We then examined not only the potential interaction between the two risk factors, but also their additive (i.e., combined) effect on performance and DMN deactivations. A significant interaction between the two cardiovascular risk factors was observed on performance, with arterial stiffness moderating the relationship between physical fitness and random n-back accuracy. The additive effect of the two factors on task performance was driven by arterial stiffness. Arterial stiffness was also found to be the driving factor when the additive effect of the two risk factors was examined on DMN deactivations. However, in posterior cingulate cortex, a hub region of the DMN, the additive effect on its deactivation was significantly higher than the effect of each risk factor alone. These results suggest that the effects of cardiovascular risks on the aging brain are complicated and multi-dimensional, with arterial stiffness moderating or driving the combined effects on performance and anterior DMN deactivations, but physical fitness contributing additional effect to posterior DMN deactivation during executive functioning.
心血管风险的增加，如高血压和低身体适应性，已被独立地与健康衰老中的默认模式网络（DMN）激活模式改变相关联。然而，心血管风险是一个多维的健康问题。因此，我们需要研究多个心血管风险因素及其对老年人认知和 DMN 激活的贡献，这一点尚未完成。目前的 fMRI 研究考察了两种常见的可改变的心血管风险因素（动脉僵硬和身体适应性）对 DMN 激活的贡献，这些激活是在执行功能和工作记忆的随机 n 回任务中涉及的。结果表明，动脉僵硬或身体适应性降低导致的心血管高风险，独立地导致了老年人在执行功能和工作记忆任务中的表现下降和两个 DMN 区域（前扣带皮层和后扣带皮层）的去激活减少。我们不仅检查了两个风险因素之间的潜在相互作用，还检查了它们对表现和 DMN 去激活的累加（即，联合）效应。两个心血管风险因素之间的显著相互作用在表现上观察到，动脉僵硬调节了身体适应性与随机 n 回准确性之间的关系。这两个因素对任务表现的累加效应是由动脉僵硬驱动的。当考察这两个风险因素的累加效应对 DMN 去激活的影响时，也发现动脉僵硬是驱动因素。然而，在后扣带皮层，DMN 的一个枢纽区域，其去激活的累加效应明显高于每个风险因素单独的效应。这些结果表明，心血管风险对衰老大脑的影响是复杂和多维的，动脉僵硬调节或驱动了表现和前 DMN 去激活的综合效应，但身体适应性对执行功能期间的后 DMN 去激活有额外的贡献。
