University of Toronto.
Rotman Research Institute, Baycrest, Toronto, Canada.
J Cogn Neurosci. 2024 Jun 1;36(6):1184-1205. doi: 10.1162/jocn_a_02159.
Healthy older adults often exhibit lower performance but increased functional recruitment of the frontoparietal control network during cognitive control tasks. According to the cortical disconnection hypothesis, age-related changes in the microstructural integrity of white matter may disrupt inter-regional neuronal communication, which in turn can impair behavioral performance. Here, we use fMRI and diffusion-weighted imaging to determine whether age-related differences in white matter microstructure contribute to frontoparietal over-recruitment and behavioral performance during a response inhibition (go/no-go) task in an adult life span sample (n = 145). Older and female participants were slower (go RTs) than younger and male participants, respectively. However, participants across all ages were equally accurate on the no-go trials, suggesting some participants may slow down on go trials to achieve high accuracy on no-go trials. Across the life span, functional recruitment of the frontoparietal network within the left and right hemispheres did not vary as a function of age, nor was it related to white matter fractional anisotropy (FA). In fact, only frontal FA and go RTs jointly mediated the association between age and no-go accuracy. Our results therefore suggest that frontal white matter cortical "disconnection" is an underlying driver of age-related differences in cognitive control, and white matter FA may not fully explain functional task-related activation in the frontoparietal network during the go/no-go task. Our findings add to the literature by demonstrating that white matter may be more important for certain cognitive processes in aging than task-related functional activation.
健康的老年人在进行认知控制任务时，通常表现出较低的表现，但前额顶叶控制网络的功能募集增加。根据皮质分离假说，白质微观结构完整性的年龄相关变化可能会破坏区域间神经元的通讯，从而损害行为表现。在这里，我们使用 fMRI 和弥散加权成像来确定在成人寿命样本（n = 145）中，白质微观结构的年龄相关差异是否会导致前额顶叶过度募集和反应抑制（go/no-go）任务中的行为表现。与年轻和男性参与者相比，年长和女性参与者的反应时间（go RTs）较慢。然而，所有年龄段的参与者在无反应试验中的准确性都相同，这表明一些参与者可能会在 go 试验中减速，以在无反应试验中获得高准确性。在整个生命周期中，左、右半球前额顶叶网络的功能募集都不会随年龄而变化，也与白质各向异性分数（FA）无关。实际上，只有额叶 FA 和 go RTs 共同介导了年龄与无反应准确性之间的关联。因此，我们的结果表明，额叶白质皮质“分离”是认知控制中与年龄相关差异的潜在驱动因素，而白质 FA 可能无法完全解释 go/no-go 任务中前额顶叶网络的功能任务相关激活。我们的研究结果通过证明在衰老过程中，白质可能比与任务相关的功能激活对某些认知过程更为重要，从而丰富了文献。
