White matter changes compromise prefrontal cortex function in healthy elderly individuals
White matter changes compromise prefrontal cortex function in healthy elderly individuals
复制标题
DOI：
10.1162/089892906775990552
复制
发表时间：
2006-03-01
影响因子：
3.2
通讯作者：
Jagust, WJ
中科院分区：
文献类型：
--
作者：
Nordahl, CW;Ranganath, C;Jagust, WJ
老年人记忆功能的改变通常归因于前额叶皮质(PFC)的功能障碍。这种功能障碍的一个机制可能是连接PFC和其解剖靶点的白质束被破坏。在这里，我们测试了白质退行性变与前额叶激活减少有关的假设。我们使用脑白质高强度(WMH)作为白质变性的标志，这是一种与老年人脑血管疾病相关的磁共振成像(MRI)发现。具体地说，我们使用结构磁共振来量化一组认知正常的老年人的WMH的程度，并测试这些测量是否可以预测在执行情景提取任务和文字工作记忆任务时观察到的前额叶活动(FMRI)的大小。我们还考察了位于额背外侧区的WMH的影响，假设背侧PFC WMH不仅与PFC功能密切相关，而且与以任务依赖的方式在解剖和功能上与PFC相关的区域有关。结果显示，整体和区域背侧PFC WMH容量的增加与PFC活动的减少有关。此外，PFC WMH的背侧体积与情景提取时内侧颞叶和前扣带回区域的活动减少以及工作记忆操作中后顶叶和前扣带回皮质的活动减少有关。这些结果表明，白质束的破坏，特别是在前额叶内，可能是与年龄相关的记忆功能变化的一种机制。
Changes in memory function in elderly individuals are often attributed to dysfunction of the prefrontal cortex (PFC). One mechanism for this dysfunction may be disruption of white matter tracts that connect the PFC with its anatomical targets. Here, we tested the hypothesis that white matter degeneration, p is associated with reduced prefrontal activation. We used white matter hyperintensities (WMH), a magnetic resonance imaging (MRI) finding associated with cerebrovascular disease in elderly individuals, as a marker for white matter degeneration. Specifically, we used structural MRI to quantify the extent of WMH in a group of cognitively normal elderly individuals and tested whether these measures were predictive of the magnitude of prefrontal activity (fMRI) observed during performance of an episodic retrieval task and a verbal working memory task. We also examined the effects of WMH located in the dorsolateral frontal regions with the hypothesis that dorsal PFC WMH would be strongly associated with not only PFC function, but also with areas that are anatomically and functionally linked to the PFC in a task-dependent manner. Results showed that increases in both global and regional dorsal PFC WMH volume were associated with decreases in PFC activity. In addition, dorsal PFC WMH volume was associated with decreased activity in medial temporal and anterior cingulate regions during episodic retrieval and decreased activity in the posterior parietal and anterior cingulate cortex during working memory performance. These results suggest that disruption of white matter tracts, especially within the PFC, may be a mechanism for age-related changes in memory functioning.