Expectancies of nicotine content have been shown to impact smokers' subjective responses and smoking behaviors. However, little is known about the neural substrates modulated by verbally induced expectancies in smokers. In this study we used functional magnetic resonance imaging (fMRI) to investigate how verbally induced expectations, regarding the presence or absence of nicotine, modulated smokers' neural response to a nicotine-free odor. While laying in the scanner, all participants (N = 24) were given a nicotine-free odor, but whereas one group was correctly informed about the absence of nicotine (control group n = 12), the other group was led to believe that the presented odor contained nicotine (expectancy group n = 12). Smokers in the expectancy group had significantly increased blood-oxygen-level-dependent (BOLD) responses during the presentation of the nicotine-free odor in the left ventral tegmental area (VTA), and in the right insula, as compared to smokers in the control group (Regions of interest analysis with pFWE-corrected p ≤ 0.05). At a more liberal uncorrected statistical level (p-unc ≤ 0.001), increased bilateral reactivity in the dorsolateral prefrontal cortex (dlPFC) was also observed in the expectancy group as compared with the control group. Our findings suggest that nicotine-expectancies induced through verbal instructions can modulate nicotine relevant brain regions, without nicotine administration, and provide further neural support for the key role that cognitive expectancies play in the cause and treatment of nicotine dependence.

中文翻译：

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尼古丁含量的口头建议在吸烟者呈现无尼古丁气味期间调节腹侧被盖神经活动

尼古丁含量的预期已被证明会影响吸烟者的主观反应和吸烟行为。然而，人们对吸烟者言语诱导的预期所调节的神经基质知之甚少。在这项研究中，我们使用功能性磁共振成像 (fMRI) 来研究口头诱导的期望（关于尼古丁的存在与否）如何调节吸烟者对不含尼古丁的气味的神经反应。当躺在扫描仪中时，所有参与者 (N = 24) 都闻到了不含尼古丁的气味，但是一组被正确告知没有尼古丁（对照组 n = 12），而另一组则认为呈现的气味含有尼古丁（期望组 n = 12）。与预期组的吸烟者相比，预期组的吸烟者在左腹侧被盖区 (VTA) 和右脑岛出现无尼古丁气味期间，血氧水平依赖性 (BOLD) 反应显着增加。对照组（感兴趣区域分析，pFWE 校正 p ≤ 0.05）。在更宽松的未校正统计水平 (p-unc ≤ 0.001) 中，与对照组相比，预期组的背外侧前额叶皮层 (dlPFC) 的双侧反应性增加。我们的研究结果表明，通过口头指令诱导的尼古丁预期可以调节尼古丁相关大脑区域，无需尼古丁给药，并为认知预期在尼古丁依赖的原因和治疗中发挥的关键作用提供进一步的神经支持。