Neurobiology of placebo effects: expectations or learning?
Neurobiology of placebo effects: expectations or learning?
复制标题
安慰剂效应的神经生物学：期望还是学习？
DOI：
10.1093/scan/nst079
复制
发表时间：
2014
影响因子：
4.2
通讯作者：
Zubieta,Jon-Kar
中科院分区：
文献类型：
--
作者：
Peciña,Marta;Stohler,ChristianS;Zubieta,Jon-Kar
Contemporary learning theories suggest that conditioning is heavily dependent on the processing of prediction errors, which signal a discrepancy between expected and observed outcomes. This line of research provides a framework through which classical theories of placebo effects, expectations and conditioning, can be reconciled. Brain regions related to prediction error processing [anterior cingulate cortex (ACC), orbitofrontal cortex or the nucleus accumbens] overlap with those involved in placebo effects. Here we examined the possibility that the magnitude of objective neurochemical responses to placebo administration would depend on individual expectation-effectiveness comparisons. We show that such comparisons and not expectationsper sepredict behavioral placebo responses and placebo-induced activation of µ-opioid receptor-mediated neurotransmission in regions relevant to error detection (e.g. ACC). Expectations on the other hand were associated with greater µ-opioid system activation in the dorsolateral prefrontal cortex but not with greater behavioral placebo responses. The results presented aid the elucidation of molecular and neural mechanisms underlying the relationship between expectation-effectiveness associations and the formation of placebo responses, shedding light on the individual differences in learning and decision making. Expectation and outcome comparisons emerge as a cognitive mechanism that beyond reward associations appears to facilitate the formation and sustainability of placebo responses.
