University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Zurich, Switzerland.
University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Zurich, Switzerland.
Neuroimage. 2020 Jul 1;214:116680. doi: 10.1016/j.neuroimage.2020.116680. Epub 2020 Feb 24.
Healthy aging is associated with weaker functional connectivity within resting state brain networks and stronger functional interaction between these networks. This phenomenon has been characterized as reduced functional segregation and has been investigated mainly in cross-sectional studies. Here, we used a longitudinal dataset which consisted of four occasions of resting state fMRI and psychometric cognitive ability data, collected from a sample of healthy older adults (baseline N = 232, age range: 64-87 y, age M = 70.8 y), to investigate the functional segregation of several well-defined resting state networks encompassing the whole brain. We characterized the ratio of within-network and between-network correlations via the well-established segregation index. Our findings showed a decrease over a 4-year interval in the functional segregation of the default mode, frontoparietal control and salience ventral attention networks. In contrast, we showed an increase in the segregation of the limbic network over the same interval. More importantly, the rate of change in functional segregation of the frontoparietal control network was associated with the rate of change in processing speed. These findings support the hypothesis of functional dedifferentiation in healthy aging as well as its role in cognitive function in elderly.
健康的衰老与静息状态大脑网络内功能连接性变弱以及这些网络之间功能交互增强有关。这种现象被描述为功能分离减少，并主要在横断面研究中进行了研究。在这里，我们使用了一个纵向数据集，该数据集由四次静息状态 fMRI 和心理认知能力数据组成，从一组健康的老年人样本中收集（基线 N=232，年龄范围：64-87 岁，平均年龄 70.8 岁），以研究涵盖整个大脑的几个明确的静息状态网络的功能分离。我们通过成熟的分离指数来描述网络内和网络间相关性的比例。我们的发现表明，在 4 年的时间间隔内，默认模式、额顶控制和突显腹侧注意网络的功能分离减少。相比之下，在同一时间段内，边缘网络的分离增加。更重要的是，额顶控制网络功能分离的变化率与处理速度的变化率相关。这些发现支持了健康衰老过程中功能去分化的假设，以及其在老年人认知功能中的作用。
