Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan Department of Internal Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan Department of Biomedical Imaging and Radiological Sciences, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan Division of Gastroenterology, Taipei Veterans General Hospital, Taipei, Taiwan Integrated Brain Research Laboratory, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan.
Pain. 2010 Jan;148(1):75-83. doi: 10.1016/j.pain.2009.10.012. Epub 2009 Dec 3.
Visceral pain/discomfort is the cardinal complaints and treatment targets for functional gastrointestinal disorders (FGID). However, effective treatment for such pain is limited and often associated with high placebo effects. The mechanisms of placebo effects in visceral pain are unclear. We used functional neuroimaging to study the central representations of the placebo effect and its anticipation during esophageal pain in healthy adults. Fourteen subjects were enrolled. Pain extent, psychophysical inventories [Pain Catastrophizing Scale (PAS), visual analogue scale (VAS) and short-form McGill questionnaire], and brain activity upon placebo intervention and upon anticipation were assessed in response to esophageal balloon distension. Large reductions of pain extent, VAS rating, short-form McGill questionnaire scores, and brain activity in the visceral pain matrix [thalamus, somatosensory cortices, insula, prefrontal cortex (PFC), anterior cingulate cortex] were observed upon placebo treatment. The aforementioned brain areas and the bilateral amygdala were significantly correlated with decreased pain extent and VAS in response to placebo. The ventral lateral PFC (VLPFC) was associated with increased activity during anticipation of visceral pain. PAS cannot predict the placebo effect in visceral pain. In conclusion, pronounced placebo analgesia was coupled with prominent changes of brain activity in visceral pain matrix, which are thus likely involved in high placebo efficacy during the treatment of visceral pain in FGID. VLPFC activation during the anticipation of placebo analgesia suggests top-down control in the modulation of pain experience.
内脏痛/不适是功能性胃肠疾病（FGID）的主要症状和治疗靶点。然而，针对此类疼痛的有效治疗方法有限，且往往与高安慰剂效应有关。安慰剂效应在内脏痛中的作用机制尚不清楚。我们使用功能神经影像学研究了健康成年人食管痛中安慰剂效应及其预期的中枢表现。纳入了 14 名受试者。通过食管球囊扩张评估了安慰剂干预和预期时的疼痛程度、心理物理量表[疼痛灾难化量表（PAS）、视觉模拟量表（VAS）和简短 McGill 问卷]和大脑活动。在安慰剂治疗时，疼痛程度、VAS 评分、简短 McGill 问卷评分和内脏痛矩阵[丘脑、躯体感觉皮质、脑岛、前额叶皮质（PFC）、前扣带回皮质]中的大脑活动明显减少。上述大脑区域和双侧杏仁核与安慰剂治疗时疼痛程度和 VAS 的降低显著相关。腹外侧前额叶皮质（VLPFC）与内脏痛预期时的活动增加相关。PAS 不能预测内脏痛的安慰剂效应。总之，明显的安慰剂镇痛与内脏痛矩阵中大脑活动的显著变化相关，这表明在 FGID 内脏痛治疗中，安慰剂的高疗效可能与这些变化有关。VLPFC 在安慰剂镇痛预期时的激活提示了在疼痛体验调节中的自上而下的控制。
