Geha P Y, Baliki M N, Chialvo D R, Harden R N, Paice J A, Apkarian A V
Department of Physiology, Northwestern University, Feinberg School of Medicine, 303 East Chicago Ave, Chicago, IL 60611, USA.
Pain. 2007 Mar;128(1-2):88-100. doi: 10.1016/j.pain.2006.09.014. Epub 2006 Oct 25.
Postherpetic neuralgia (PHN) is a debilitating chronic pain condition, yet there is a lack of knowledge regarding underlying brain activity. Here we identify brain regions involved in spontaneous pain of PHN (n=11) and determine its modulation with Lidoderm therapy (patches of 5% lidocaine applied to the PHN affected body part). Continuous ratings of fluctuations of spontaneous pain during fMRI were contrasted to ratings of fluctuations of a bar observed during scanning, at three sessions: (1) pre-treatment baseline, (2) after 6h of Lidoderm treatment, and (3) after 2 weeks of Lidoderm use. Overall brain activity for spontaneous pain of PHN involved affective and sensory-discriminative areas: thalamus, primary and secondary somatosensory, insula and anterior cingulate cortices, as well as areas involved in emotion, hedonics, reward, and punishment: ventral striatum, amygdala, orbital frontal cortex, and ventral tegmental area. Generally, these activations decreased at sessions 2 and 3, except right anterior insular activity which increased with treatment. The sensory and affective activations only responded to the short-term treatment (6h of Lidoderm); while the ventral striatum and amygdala (reward-related regions) decreased mainly with longer-term treatment (2 weeks of Lidoderm). Pain properties: average magnitude of spontaneous pain, and responses on Neuropathic Pain Scale (NPS), decreased with treatment. The ventral striatal and amygdala activity best reflected changes in NPS, which was modulated only with longer-term treatment. The results show a specific brain activity pattern for PHN spontaneous pain, and implicate areas involved in emotions and reward as best reflecting changes in pain with treatment.
带状疱疹后神经痛（PHN）是一种使人衰弱的慢性疼痛病症，但对于其潜在的大脑活动仍缺乏了解。在此，我们确定了参与PHN自发性疼痛的脑区（n = 11），并确定了利多卡因贴剂疗法（将5%利多卡因贴剂应用于PHN受累身体部位）对其的调节作用。在功能磁共振成像（fMRI）期间，对自发性疼痛波动的连续评分与扫描期间观察到的条形图波动评分在三个阶段进行了对比：（1）治疗前基线，（2）利多卡因治疗6小时后，以及（3）使用利多卡因2周后。PHN自发性疼痛的总体大脑活动涉及情感和感觉辨别区域：丘脑、初级和次级躯体感觉区、岛叶和前扣带回皮质，以及涉及情绪、享乐、奖赏和惩罚的区域：腹侧纹状体、杏仁核、眶额皮质和腹侧被盖区。一般来说，这些激活在第2和第3阶段减少，但右侧前岛叶活动随治疗增加。感觉和情感激活仅对短期治疗（利多卡因6小时）有反应；而腹侧纹状体和杏仁核（与奖赏相关的区域）主要在长期治疗（利多卡因2周）后减少。疼痛特性：自发性疼痛的平均强度以及神经病理性疼痛量表（NPS）上的反应随治疗而降低。腹侧纹状体和杏仁核活动最能反映NPS的变化，而NPS仅在长期治疗时受到调节。结果显示了PHN自发性疼痛的特定大脑活动模式，并表明涉及情绪和奖赏的区域最能反映治疗中疼痛的变化。
