Faculty of Medicine, University of Cologne, Köln, Germany.
Department of Psychology, University of Victoria, Victoria, British Columbia, Canada.
Brain Connect. 2020 Sep;10(7):377-384. doi: 10.1089/brain.2019.0724. Epub 2020 Aug 19.
Vast increases in life expectancy over the last century have led to shifts in population demographics and the emergence of a largely aged population, globally. This has led to a need to understand neurobiological changes associated with healthy aging. Studies on age-related changes in functional connectivity networks have largely been cross-sectional and focused on the default mode network (DMN). The current study investigated longitudinal changes in functional connectivity in multiple resting-state networks over 4 years of aging in cognitively normal older adults. Resting-state functional magnetic resonance imaging scans from older adults ( = 16) who maintained "cognitive normal" status over 4 years were retrieved at baseline and follow-up from the Alzheimer's Disease Neuroimaging Initiative database. A seed-based approach was executed in Functional MRI of the Brain Software Library (FSL) to examine significant changes in functional connectivity within the DMN, frontoparietal network (FPN), and salience network (SN) within subjects over time. Results indicated significantly ( < 0.05, corrected) reduced functional connectivity in the FPN and SN, but not in the DMN at year 4 compared with baseline in older adults who were cognitively stable. The current study highlights the importance of a longitudinal approach for understanding changes in functional connectivity. The findings also underscore the need to examine multiple networks within the same participants, given that changes were apparent in the FPN and SN but not in the DMN. Future studies should also examine changes in internetwork connectivity as well as shifts in structural connectivity over time. Impact statement Investigations of age-related changes in functional connectivity have largely been cross-sectional and focused on the default mode network (DMN). The current study examined the DMN as well as the frontoparietal network (FN) and salience network (SN), in a group of healthy aging adults over four years. The results revealed decreased functional connectivity over time, in the FN and SN, but not the DMN. These findings provide insights about the healthy aging brain. They also underscore the need to broaden the scope of functional connectivity analyses beyond the DMN and highlight the use of longitudinal methods.
上个世纪，预期寿命的大幅延长导致了全球人口结构的转变和老年人口的大量出现。这就需要了解与健康衰老相关的神经生物学变化。关于与年龄相关的功能连接网络变化的研究大多是横断面的，并且集中在默认模式网络 (DMN)。本研究调查了认知正常的老年人在 4 年的衰老过程中多个静息态网络的功能连接的纵向变化。从阿尔茨海默病神经影像学倡议 (Alzheimer's Disease Neuroimaging Initiative) 数据库中检索到在 4 年内保持“认知正常”状态的老年受试者 ( = 16) 的静息态功能磁共振成像 (fMRI) 扫描的基线和随访数据。使用基于种子的方法在大脑功能连接磁共振成像软件库 (FSL) 中执行，以检查随时间变化受试者内在 DMN、额顶网络 (FPN) 和突显网络 (SN) 中的功能连接的显著变化。结果表明，与基线相比，在认知稳定的老年人中，与基线相比，在第 4 年时，FPN 和 SN 的功能连接显著降低 ( < 0.05，校正)，而 DMN 则没有。本研究强调了采用纵向方法来理解功能连接变化的重要性。这些发现还强调了需要在同一参与者中检查多个网络，因为 FPN 和 SN 中的变化是明显的，而 DMN 中则没有。未来的研究还应该检查网络间连接的变化以及随着时间的推移结构连接的变化。
