Lockhart Samuel N, Luck Steven J, Geng Joy, Beckett Laurel, Disbrow Elizabeth A, Carmichael Owen, DeCarli Charles
Imaging of Dementia and Aging Lab, University of California Davis, Davis, CA, United States of America; Department of Neurology, University of California Davis, Davis, CA, United States of America; Neuroscience Graduate Group, University of California Davis, Davis, CA, United States of America.
Neuroscience Graduate Group, University of California Davis, Davis, CA, United States of America; Department of Psychology, University of California Davis, Davis, CA, United States of America; Center for Mind and Brain, University of California Davis, Davis, CA, United States of America.
PLoS One. 2015 Mar 20;10(3):e0122445. doi: 10.1371/journal.pone.0122445. eCollection 2015.
The mechanisms by which aging and other processes can affect the structure and function of brain networks are important to understanding normal age-related cognitive decline. Advancing age is known to be associated with various disease processes, including clinically asymptomatic vascular and inflammation processes that contribute to white matter structural alteration and potential injury. The effects of these processes on the function of distributed cognitive networks, however, are poorly understood. We hypothesized that the extent of magnetic resonance imaging white matter hyperintensities would be associated with visual attentional control in healthy aging, measured using a functional magnetic resonance imaging search task. We assessed cognitively healthy older adults with search tasks indexing processing speed and attentional control. Expanding upon previous research, older adults demonstrate activation across a frontal-parietal attentional control network. Further, greater white matter hyperintensity volume was associated with increased activation of a frontal network node independent of chronological age. Also consistent with previous research, greater white matter hyperintensity volume was associated with anatomically specific reductions in functional magnetic resonance imaging functional connectivity during search among attentional control regions. White matter hyperintensities may lead to subtle attentional network dysfunction, potentially through impaired frontal-parietal and frontal interhemispheric connectivity, suggesting that clinically silent white matter biomarkers of vascular and inflammatory injury can contribute to differences in search performance and brain function in aging, and likely contribute to advanced age-related impairments in cognitive control.
衰老和其他过程影响脑网络结构与功能的机制，对于理解正常的年龄相关认知衰退至关重要。已知年龄增长与各种疾病过程相关，包括临床上无症状的血管和炎症过程，这些过程会导致白质结构改变和潜在损伤。然而，这些过程对分布式认知网络功能的影响却知之甚少。我们假设，使用功能磁共振成像搜索任务测量，磁共振成像白质高信号的程度与健康衰老中的视觉注意力控制有关。我们用索引处理速度和注意力控制的搜索任务评估了认知健康的老年人。在先前研究的基础上，老年人在额顶叶注意力控制网络中表现出激活。此外，更大的白质高信号体积与一个额叶网络节点的激活增加有关，且与实际年龄无关。同样与先前研究一致的是，更大的白质高信号体积与注意力控制区域搜索期间功能磁共振成像功能连接在解剖学上特定的减少有关。白质高信号可能会导致微妙的注意力网络功能障碍，可能是通过额叶 - 顶叶和额叶半球间连接受损，这表明血管和炎症损伤的临床无症状白质生物标志物可能导致衰老中搜索表现和脑功能的差异，并可能导致与年龄相关的认知控制高级损伤。
