Klucken Tim, Schweckendiek Jan, Merz Christian J, Vaitl Dieter, Stark Rudolf
Department of Psychotherapy and Systems Neuroscience and Bender Institute of Neuroimaging, Justus Liebig University Giessen, Germany.
Behav Neurosci. 2013 Jun;127(3):380-6. doi: 10.1037/a0032331.
Disgust extinction is an important mechanism relevant for the treatment of psychiatric disorders. However, only a few studies have investigated disgust extinction. Moreover, because disgust sensitivity (DS) is considered as a relevant factor for learning processes, this study also investigated the potential relationship between DS and disgust extinction learning. The aim of this study was to explore the neuronal correlates of disgust extinction, as well as changes in skin conductance responses (SCRs) and evaluative conditioning. Twenty subjects were exposed to a differential extinction paradigm, in which a previous conditioned, and now unreinforced, stimulus (conditioned stimulus, CS+) was compared to a second stimulus (CS-), which was previously not associated with the unconditioned stimulus (UCS). Extinction learning was measured on three different response levels (BOLD responses, SCRs, and evaluative conditioning). Regarding evaluative conditioning, the CS+ was rated as more unpleasant than the CS-. Interestingly, significantly increased amygdala responses and SCRs toward to the CS- were observed. Finally, a (negative) trend was found between DS scores and BOLD responses of the prefrontal cortex. The present findings showed a dissociation of different response levels. The increased CS- responses could be explained by the assumption that the increased amygdala activity may reflect a safety learning signal during the first extinction trials and the subjective focus may therefore shift from the CS+ to the CS-. The correlation finding supports previous studies postulating that DS hampers extinction processes. The present results point toward dissociations between the response levels in context of extinction processes.
厌恶消退是与精神疾病治疗相关的重要机制。然而，仅有少数研究对厌恶消退进行了调查。此外，由于厌恶敏感性（DS）被视为学习过程的一个相关因素，本研究还调查了DS与厌恶消退学习之间的潜在关系。本研究的目的是探究厌恶消退的神经关联，以及皮肤电反应（SCR）和评价性条件作用的变化。20名受试者被置于一种差异消退范式中，在此范式下，将先前已形成条件反射且现在不再强化的刺激（条件刺激，CS+）与第二种刺激（CS-）进行比较，后者先前未与无条件刺激（UCS）相关联。在三个不同的反应水平（血氧水平依赖反应、SCR和评价性条件作用）上测量消退学习。关于评价性条件作用，CS+被评定为比CS-更令人不快。有趣的是，观察到杏仁核对CS-的反应和SCR显著增加。最后，在DS分数与前额叶皮质的血氧水平依赖反应之间发现了一种（负向）趋势。本研究结果显示了不同反应水平的分离。CS-反应增加可以通过以下假设来解释：杏仁核活动增加可能反映了首次消退试验期间的安全学习信号，因此主观关注点可能从CS+转移到CS-。相关性研究结果支持了先前的研究，这些研究假定DS会阻碍消退过程。本研究结果表明在消退过程中反应水平之间存在分离。
