Mechanisms of placebo analgesia:: rACC recruitment of a subcortical antinociceptive network
Mechanisms of placebo analgesia:: rACC recruitment of a subcortical antinociceptive network
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DOI：
10.1016/j.pain.2005.08.027
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发表时间：
2006-01-01
期刊：
影响因子：
7.4
通讯作者：
Büchel, C
中科院分区：
文献类型：
--
作者：
Bingel, U;Lorenz, J;Büchel, C
安慰剂止痛是痛觉认知调节的最显著的例子之一，其潜在的机制终于开始被理解。根据药理学研究，内源性阿片系统是安慰剂止痛所必需的。最近的功能成像数据表明，吻侧前扣带回皮质(RACC)是这种内源性疼痛控制的关键皮质区。因此，我们假设安慰剂止痛会招募rACC以外的其他脑区，rACC与这些脑区的相互作用作为自上而下机制的一部分，介导了阿片依赖的内源性抗伤害感受。19名健康受试者接受了双手背部疼痛的激光刺激，其中一人接受了假止痛膏(安慰剂)治疗。疼痛刺激之前有一个听觉提示，指示下一次激光刺激的一侧。使用事件相关功能磁共振成像评估在安慰剂和非安慰剂条件下对痛苦的激光刺激的BOLD反应。在确认了rACC中与安慰剂相关的活动后，一项连接性分析确定了rACC活动对安慰剂依赖的双侧杏仁核和中脑导水管周围灰质(PAG)的贡献。这一发现支持了这样的观点，即安慰剂止痛依赖于rACC与皮质下结构的功能连接的增强，而皮质下结构对条件性学习和痛觉下行抑制至关重要。(C)2005年国际疼痛研究协会。爱思唯尔出版，版权所有。
Placebo analgesia is one of the most striking examples of the cognitive modulation of pain perception and the underlying mechanisms are finally beginning to be understood. According to pharmacological studies, the endogenous opioid system is essential for placebo analgesia. Recent functional imaging data provides evidence that the rostral anterior cingulate cortex (rACC) represents a crucial cortical area for this type of endogenous pain control. We therefore hypothesized that placebo analgesia recruits other brain areas outside the rACC and that interactions of the rACC with these brain areas mediate opioid-dependent endogenous antinociception as part of a top-down mechanism. Nineteen healthy subjects received and rated painful laser stimuli to the dorsum of both hands, one of them treated with a fake analgesic cream (placebo). Painful stimulation was preceded by an auditory cue, indicating the side of the next laser stimulation. BOLD-responses to the painful laser-stimulation during the placebo and no-placebo condition were assessed using event-related fMRI. After having confirmed placebo related activity in the rACC, a connectivity analysis identified placebo dependent contributions of rACC activity with bilateral amygdalae and the periaqueductal gray (PAG). This finding supports the view that placebo analgesia depends on the enhanced functional connectivity of the rACC with subcortical brain structures that are crucial for conditioned learning and descending inhibition of nociception. (c) 2005 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.