Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305-5723, USA.
Cereb Cortex. 2011 Oct;21(10):2272-81. doi: 10.1093/cercor/bhq297. Epub 2011 Mar 2.
The default mode network (DMN) comprises brain structures maximally active at rest. Disturbance of network nodes or their connections occurs with some neuropsychiatric conditions and may underlie associated dysfunction. DMN connectivity has not been examined in alcoholism, which is marked by compromised DMN nodes and impaired spatial working memory. To test whether performance would be related to DMN integrity, we examined DMN functional connectivity using functional magnetic resonance imaging (fMRI) data and graph theory analysis. We assumed that disruption of short paths between network nodes would attenuate processing efficiency. Alcoholics and controls were scanned at rest and during a spatial working memory task. At rest, the spontaneous slow fluctuations of fMRI signals in the posterior cingulate and cerebellar regions in alcoholics were less synchronized than in controls, indicative of compromised functional connectivity. Graph theory analysis indicated that during rest, alcoholics had significantly lower efficiency indices than controls between the posterior cingulate seed and multiple cerebellar sites. Greater efficiency in several connections correlated with longer sobriety in alcoholics. During the task, on which alcoholics performed on par with controls, connectivity between the left posterior cingulate seed and left cerebellar regions was more robust in alcoholics than controls and suggests compensatory networking to achieve normal performance.
默认模式网络（DMN）由在休息时活动最强烈的大脑结构组成。一些神经精神疾病会干扰网络节点或其连接，这可能是相关功能障碍的基础。酒精中毒症中尚未检查 DMN 连接，其特征是 DMN 节点受损和空间工作记忆受损。为了检验表现是否与 DMN 完整性有关，我们使用功能磁共振成像（fMRI）数据和图论分析来检查 DMN 功能连接。我们假设网络节点之间的短路径中断会降低处理效率。对酒精中毒者和对照组进行了静息状态和空间工作记忆任务下的扫描。在静息状态下，酒精中毒者的后扣带回和小脑区域的 fMRI 信号的自发缓慢波动比对照组的同步性差，表明功能连接受损。图论分析表明，在静息状态下，与对照组相比，后扣带回种子与多个小脑部位之间的酒精中毒者效率指数明显较低。酒精中毒者的几个连接的效率越高，与更长的戒酒时间相关。在任务中，酒精中毒者的表现与对照组相当，与对照组相比，酒精中毒者的左后扣带回种子与左小脑区域之间的连接更为稳定，这表明存在代偿性网络以实现正常表现。
