Research Centre for Neural Engineering, Institute of Biomedical and Health Engineering, Shenzhen Institute of Advance Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
Neurosci Bull. 2009 Oct;25(5):277-82. doi: 10.1007/s12264-009-0907-2.
Placebo has been reported to exert beneficial effects in patients regarding the treatment of pain. Human functional neuroimaging technology can study the intact human brain to elucidate its functional neuroanatomy and the neurobiological mechanism of the placebo effect. Blood flow measurement using functional magnetic resonance imaging and positron emission tomography (PET) has revealed that analgesia is related to decreased neural activities in pain-modulatory brain regions, such as the rostral anterior cingulate cortex (rACC), insula, thalamus, and brainstem including periaqueductal gray (PAG) and ventromedial medulla. The endogenous opioid system and its activation of mu-opioid receptors are thought to mediate the observed effects of placebo. The mu-opioid receptor-selective radiotracer-labeled PET studies show that the placebo effects are accompanied by reduction in activation of opioid neural transmission in pain-sensitive brain regions, including rACC, prefrontal cortex, insula, thalamus, amygdala, nucleus accumbens (NAC) and PAG. Further PET studies with dopamine D2/D3 receptor-labeling radiotracer demonstrate that basal ganglia including NAC are related to placebo analgesic responses. NAC dopamine release induced by placebo analgesia is related to expectation of analgesia. These data indicate that the aforementioned brain regions and neurotransmitters such as endogenous opioid and dopamine systems contribute to placebo analgesia.
安慰剂已被报道在治疗疼痛的患者中发挥有益的作用。人类功能神经影像学技术可以研究完整的人脑，以阐明其功能神经解剖结构和安慰剂效应的神经生物学机制。使用功能磁共振成像和正电子发射断层扫描 (PET) 的血流测量已经表明，镇痛与疼痛调节脑区（如前扣带回皮质的前部（rACC）、岛叶、丘脑和包括中脑导水管周围灰质（PAG）和腹内侧髓质的脑干）的神经活动减少有关。内源性阿片系统及其对 μ-阿片受体的激活被认为介导了安慰剂的观察到的效果。μ-阿片受体选择性放射性示踪剂标记的 PET 研究表明，安慰剂效应伴随着疼痛敏感脑区（包括 rACC、前额叶皮层、岛叶、丘脑、杏仁核、伏隔核（NAC）和 PAG）中阿片类神经传递的激活减少。进一步使用多巴胺 D2/D3 受体标记放射性示踪剂的 PET 研究表明，包括 NAC 的基底节与安慰剂镇痛反应有关。NAC 多巴胺释放诱导的安慰剂镇痛与镇痛的预期有关。这些数据表明，上述脑区和神经递质（如内源性阿片和多巴胺系统）有助于安慰剂镇痛。
