Brain Imaging and Analysis Center, Duke University Medical Center, Box 3918, Durham, NC, 27710, USA.
Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, 27710, USA.
Brain Struct Funct. 2024 Sep;229(7):1533-1559. doi: 10.1007/s00429-024-02807-2. Epub 2024 Jun 10.
Previous magnetic resonance imaging (MRI) research suggests that aging is associated with a decrease in the functional interconnections within and between groups of locally organized brain regions (modules). Further, this age-related decrease in the segregation of modules appears to be more pronounced for a task, relative to a resting state, reflecting the integration of functional modules and attentional allocation necessary to support task performance. Here, using graph-theoretical analyses, we investigated age-related differences in a whole-brain measure of module connectivity, system segregation, for 68 healthy, community-dwelling individuals 18-78 years of age. We obtained resting-state, task-related (visual search), and structural (diffusion-weighted) MRI data. Using a parcellation of modules derived from the participants' resting-state functional MRI data, we demonstrated that the decrease in system segregation from rest to task (i.e., reconfiguration) increased with age, suggesting an age-related increase in the integration of modules required by the attentional demands of visual search. Structural system segregation increased with age, reflecting weaker connectivity both within and between modules. Functional and structural system segregation had qualitatively different influences on age-related decline in visual search performance. Functional system segregation (and reconfiguration) influenced age-related decline in the rate of visual evidence accumulation (drift rate), whereas structural system segregation contributed to age-related slowing of encoding and response processes (nondecision time). The age-related differences in the functional system segregation measures, however, were relatively independent of those associated with structural connectivity.
先前的磁共振成像（MRI）研究表明，衰老与局部组织脑区（模块）内和模块间的功能连接减少有关。此外，与静息状态相比，任务状态下模块分离的这种与年龄相关的下降似乎更为明显，反映了支持任务执行的功能模块的整合和注意力分配。在这里，我们使用图论分析研究了 68 名健康的社区居住者在全脑模块连接的整体大脑测量中与年龄相关的差异，年龄在 18-78 岁之间。我们获得了静息状态、任务相关（视觉搜索）和结构（扩散加权）MRI 数据。使用源自参与者静息状态功能 MRI 数据的模块划分，我们证明了从静息到任务（即重新配置）的系统分离的减少随年龄增加，这表明与视觉搜索的注意力需求相关的模块的整合随着年龄的增长而增加。结构系统分离随年龄增加，反映了模块内和模块间的连接减弱。功能和结构系统分离对视觉搜索性能的与年龄相关的下降有不同的影响。功能系统分离（和重新配置）影响视觉证据积累（漂移率）的与年龄相关的下降，而结构系统分离则导致编码和反应过程（非决策时间）的与年龄相关的减慢。然而，功能系统分离测量中的与年龄相关的差异与与结构连通性相关的差异相对独立。
