Schweinhardt Petra, Glynn Chris, Brooks Jonathan, McQuay Henry, Jack Tim, Chessell Iain, Bountra Chas, Tracey Irene
Department of Human Anatomy and Genetics, Oxford University, South Parks Road, Oxford OX1 1QX, UK.
Neuroimage. 2006 Aug 1;32(1):256-65. doi: 10.1016/j.neuroimage.2006.03.024. Epub 2006 May 5.
Previous human imaging studies have revealed a network of brain regions involved in the processing of allodynic pain; this includes prefrontal areas, insula, cingulate cortex, primary and secondary somatosensory cortices and parietal association areas. In this study, the neural correlates of the perceived intensity of allodynic pain in neuropathic pain patients were investigated. In eight patients, dynamic mechanical allodynia was provoked and brain responses recorded using functional magnetic resonance imaging (fMRI). Voxels in which the magnitude of fMRI signal correlated linearly with the ratings of allodynic pain across the group were determined in a whole brain analysis using a general linear model. To ensure that activation reflected only allodynic pain ratings, a nuisance variable containing ratings of ongoing pain was included in the analysis. We found that the magnitude of activation in the caudal anterior insula (cAI) correlates with the perceived intensity of allodynic pain across subjects, independent of the level of ongoing pain. However, the peak of activation in the allodynic condition was located in the rostral portion (rAI). This matches the representation of other clinical pain syndromes, confirmed by a literature review. In contrast, experimental pain in healthy volunteers resides predominantly in the cAI, as shown by the same literature review. Taken together, our data and the literature review suggest a functional segregation of anterior insular cortex.
先前的人体成像研究揭示了一个参与处理异常性疼痛的脑区网络；这包括前额叶区域、脑岛、扣带回皮质、初级和次级躯体感觉皮质以及顶叶联合区域。在本研究中，对神经性疼痛患者中异常性疼痛的感知强度的神经相关性进行了调查。在八名患者中，诱发动态机械性异常性疼痛，并使用功能磁共振成像（fMRI）记录脑反应。在全脑分析中，使用一般线性模型确定fMRI信号幅度与全组异常性疼痛评分呈线性相关的体素。为确保激活仅反映异常性疼痛评分，分析中纳入了一个包含持续性疼痛评分的干扰变量。我们发现，尾侧前脑岛（cAI）的激活幅度与受试者的异常性疼痛感知强度相关，与持续性疼痛水平无关。然而，异常性疼痛状态下的激活峰值位于嘴侧部分（rAI）。经文献综述证实，这与其他临床疼痛综合征的表现相符。相比之下，同一文献综述表明，健康志愿者的实验性疼痛主要位于cAI。综合来看，我们的数据和文献综述表明前脑岛皮质存在功能分离。
