Predicting individual differences in placebo analgesia: contributions of brain activity during anticipation and pain experience.
Predicting individual differences in placebo analgesia: contributions of brain activity during anticipation and pain experience.
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DOI：
10.1523/jneurosci.3420-10.2011
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发表时间：
2011-01-12
期刊：
影响因子：
--
通讯作者：
Rilling JK
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文献类型：
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作者：
Wager TD;Atlas LY;Leotti LA;Rilling JK
最近的研究已经确定了安慰剂镇痛的大脑相关性，但没有评估大脑活动模式如何准确地预测安慰剂反应的个体差异。我们重新分析了两项安慰剂镇痛功能磁共振成像研究 (N = 47) 的数据，利用疼痛预期和体验期间的功能磁共振成像活动模式来预测新受试者在安慰剂镇痛和安慰剂引起的疼痛处理变化方面的得分。我们使用了交叉验证的回归程序 LASSO-PCR，它提供了预测准确性的无偏估计以及对预测最重要的区域的可解释图。额顶叶网络预期活动的增加和后岛/颞叶网络预期活动的减少预示着安慰剂镇痛。整个大脑皮层的预期活动模式预测安慰剂反应存在中等程度的差异（总体约为 12%，仅研究 2 约为 40%），考虑到多种可能的影响因素，这是相当大的。最具预测性的区域是那些与情绪评估相关的区域，而不是与认知控制或疼痛处理相关的区域。在疼痛期间，边缘和旁边缘区域的减少最能预测安慰剂镇痛。典型疼痛处理区域内的反应解释了安慰剂镇痛的显着差异，但效果模式与伤害性处理的广泛减少不一致。总之，研究结果表明，情绪评估回路的参与会导致安慰剂镇痛的个体差异，而不是早期抑制伤害性处理。这种方法提供了一个框架，随着新研究为未来的预测模型提供更精确的信息，预测准确性将得到提高。
Recent studies have identified brain correlates of placebo analgesia, but none have assessed how accurately patterns of brain activity can predict individual differences in placebo responses. We reanalyzed data from two fMRI studies of placebo analgesia (N = 47), using patterns of fMRI activity during the anticipation and experience of pain to predict new subjects’ scores on placebo analgesia and placebo-induced changes in pain processing. We used a cross-validated regression procedure, LASSO-PCR, which provided both unbiased estimates of predictive accuracy and interpretable maps of which regions are most important for prediction. Increased anticipatory activity in a frontoparietal network and decreases in a posterior insular/temporal network predicted placebo analgesia. Patterns of anticipatory activity across the cortex predicted a moderate amount of variance in the placebo response (~12% overall, ~40% for study 2 alone), which is substantial considering the multiple likely contributing factors. The most predictive regions were those associated with emotional appraisal, rather than cognitive control or pain processing. During pain, decreases in limbic and paralimbic regions most strongly predicted placebo analgesia. Responses within canonical pain-processing regions explained significant variance in placebo analgesia, but the pattern of effects was inconsistent with widespread decreases in nociceptive processing. Together, the findings suggest that engagement of emotional appraisal circuits drives individual variation in placebo analgesia, rather than early suppression of nociceptive processing. This approach provides a framework that will allow prediction accuracy to increase as new studies provide more precise information for future predictive models.