Default-mode network activity distinguishes Alzheimer's disease from healthy aging: Evidence from functional MRI
Default-mode network activity distinguishes Alzheimer's disease from healthy aging: Evidence from functional MRI
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DOI：
10.1073/pnas.0308627101
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发表时间：
2004-03-30
影响因子：
11.1
通讯作者：
Menon, V
中科院分区：
文献类型：
--
作者：
Greicius, MD;Srivastava, G;Menon, V
最近的功能成像研究显示，在一个分布式网络的皮层区域，表征休息状态，或默认模式，人类大脑的共激活。在这个网络中涉及的大脑区域中，包括后扣带皮层和下顶叶在内的几个区域在阿尔茨海默病（AD）的早期也显示出代谢下降。我们推断，默认模式的网络活动可能因此在AD中异常。为了验证这一假设，我们使用独立成分分析来分离一组13名轻度AD受试者和一组13名年龄匹配的老年对照者的网络，因为他们执行了一个简单的感觉运动处理任务。三个重要的调查结果报告。在所有组中检测到的海马体的显著共激活表明，默认模式网络与情景记忆处理密切相关。AD组显示后扣带回和海马的静息态活动减少，这表明这两个区域之间的连接中断导致了早期AD的正电子发射断层扫描研究中常见的后扣带回代谢低下。最后，在个体受试者水平上应用的拟合优度分析表明，默认模式网络中的活动可能最终证明是早期AD的敏感和特异性生物标志物。
Recent functional imaging studies have revealed coactivation in a distributed network of cortical regions that characterizes the resting state, or default mode, of the human brain. Among the brain regions implicated in this network, several, including the posterior cingulate cortex and inferior parietal lobes, have also shown decreased metabolism early in the course of Alzheimer's disease (AD). We reasoned that default-mode network activity might therefore be abnormal in AD. To test this hypothesis, we used independent component analysis to isolate the network in a group of 13 subjects with mild AD and in a group of 13 age-matched elderly controls as they performed a simple sensory-motor processing task. Three important findings are reported. Prominent coactivation of the hippocampus, detected in all groups, suggests that the default-mode network is closely involved with episodic memory processing. The AD group showed decreased resting-state activity in the posterior cingulate and hippocampus, suggesting that disrupted connectivity between these two regions accounts for the posterior cingulate hypometabolism commonly detected in positron emission tomography studies of early AD. Finally, a goodness-of-fit analysis applied at the individual subject level suggests that activity in the default-mode network may ultimately prove a sensitive and specific biomarker for incipient AD.