Kong Jian, Kaptchuk Ted J, Polich Ginger, Kirsch Irving, Vangel Mark, Zyloney Carolyn, Rosen Bruce, Gollub Randy L
Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129, USA.
Neuroimage. 2009 Sep;47(3):1066-76. doi: 10.1016/j.neuroimage.2009.05.087. Epub 2009 Jun 6.
It is well established that expectation can significantly modulate pain perception. In this study, we combined an expectancy manipulation model and fMRI to investigate how expectation can modulate acupuncture treatment. Forty-eight subjects completed the study. The analysis on two verum acupuncture groups with different expectancy levels indicates that expectancy can significantly influence acupuncture analgesia for experimental pain. Conditioning positive expectation can amplify acupuncture analgesia as detected by subjective pain sensory rating changes and objective fMRI signal changes in response to calibrated noxious stimuli. Diminished positive expectation appeared to inhibit acupuncture analgesia. This modulation effect is spatially specific, inducing analgesia exclusively in regions of the body where expectation is focused. Thus, expectation should be used as an important covariate in future studies evaluating acupuncture efficacy. In addition, we also observed dissociation between subjective reported analgesia and objective fMRI signal changes to calibrated pain in the analysis across all four groups. We hypothesize that as a peripheral-central modulation, acupuncture needle stimulation may inhibit incoming noxious stimuli; while as a top-down modulation, expectancy (placebo) may work through the emotional circuit.
众所周知，期望能够显著调节疼痛感知。在本研究中，我们结合了期望操纵模型和功能磁共振成像（fMRI）来探究期望如何调节针刺治疗。48名受试者完成了该研究。对两个具有不同期望水平的真针刺组的分析表明，期望能够显著影响针对实验性疼痛的针刺镇痛效果。通过主观疼痛感觉评分变化以及对校准后的有害刺激做出反应时的客观fMRI信号变化检测发现，调节积极期望能够增强针刺镇痛效果。积极期望的降低似乎会抑制针刺镇痛。这种调节作用具有空间特异性，仅在期望集中的身体区域诱导镇痛。因此，在未来评估针刺疗效的研究中，期望应作为一个重要的协变量。此外，在对所有四组的分析中，我们还观察到主观报告的镇痛与对校准疼痛的客观fMRI信号变化之间的分离。我们推测，作为一种外周 - 中枢调节，针刺刺激可能会抑制传入的有害刺激；而作为一种自上而下的调节，期望（安慰剂）可能通过情感回路起作用。
