Institute for Advanced Biomedical Technologies and Department of Clinical Sciences and Bio-imaging, G. D'Annunzio University Foundation, via dei Vestini 33, 66013 Chieti, Italy.
Radiology. 2009 Dec;253(3):797-804. doi: 10.1148/radiol.2533090602. Epub 2009 Sep 29.
To investigate whether default mode network (DMN) spatial properties can be directly affected by pain, with a comparison of painful and nonpainful conditions.
The authors performed a functional magnetic resonance (MR) imaging study, approved by the local institutional ethics committee, involving 10 healthy male subjects (age range, 18-45 years) who gave written informed consent. The subjects underwent two experimental sessions of median nerve electrical stimulation at painful and nonpainful levels. Independent component analysis of the functional MR imaging data was performed to determine the DMN spatiotemporal pattern. Group-level DMN connectivity maps for painful and nonpainful conditions were obtained (P < .001, corrected with false discovery rate). The contrast between the connectivity maps in the two conditions was also computed (P < .05, corrected with false discovery rate).
The DMN maintained its typical temporal properties but was subject to modifications in connectivity pattern during painful stimulation, affecting the brain areas associated with pain processing. Increased connectivity in painful conditions was found mainly in the left prefrontal cortex and posterior cingulate cortex-precuneus, and decreased connectivity was found in the lateral parietal cortex.
Study findings were in line with the impairments of the DMN reported in patients with chronic pain. They support the hypothesis that alteration of the DMN connectivity pattern localized in specific brain areas during acute pain, if repeated across time, might induce permanent changes that could disrupt the DMN functional architecture.
探讨默认模式网络（DMN）的空间特性是否可直接受到疼痛的影响，并对疼痛和非疼痛状态进行比较。
作者进行了一项经当地机构伦理委员会批准的功能磁共振成像（MR）研究，共纳入 10 名健康男性志愿者（年龄 18-45 岁），均签署了知情同意书。志愿者接受了两次正中神经电刺激，刺激水平分别为疼痛和非疼痛。对功能磁共振成像数据进行独立成分分析，以确定 DMN 的时空模式。获得疼痛和非疼痛状态下的 DMN 连接图（P <.001，采用错误发现率校正）。还计算了两种状态下连接图之间的对比（P <.05，采用错误发现率校正）。
DMN 保持了其典型的时间特性，但在疼痛刺激时其连接模式发生了变化，影响了与疼痛处理相关的脑区。在疼痛状态下，发现连接性增加主要发生在左侧前额叶皮质和后扣带回-楔前叶，而外侧顶叶皮质的连接性降低。
研究结果与慢性疼痛患者 DMN 受损的报告一致。它们支持这样一种假说，即在急性疼痛期间，特定脑区 DMN 连接模式的改变，如果反复发生，可能会导致永久性变化，从而破坏 DMN 的功能结构。
