Health, Medical and Neuropsychology Unit, Faculty of Social and Behavioural Sciences, Institute of Psychology, Leiden University, Leiden, the Netherlands.
Leiden Institute for Brain and Cognition, Leiden, the Netherlands.
PLoS One. 2020 Mar 19;15(3):e0229692. doi: 10.1371/journal.pone.0229692. eCollection 2020.
It has been demonstrated that secretion of several hormones can be classically conditioned, however, the underlying brain responses of such conditioning have never been investigated before. In this study we aimed to investigate how oxytocin administration and classically conditioned oxytocin influence brain responses. In total, 88 females were allocated to one of three groups: oxytocin administration, conditioned oxytocin, or placebo, and underwent an experiment consisting of three acquisition and three evocation days. Participants in the conditioned group received 24 IU of oxytocin together with a conditioned stimulus (CS) during three acquisition days and placebo with the CS on three evocation days. The oxytocin administration group received 24 IU of oxytocin and the placebo group received placebo during all days. On the last evocation day, fMRI scanning was performed for all participants during three tasks previously shown to be affected by oxytocin: presentation of emotional faces, crying baby sounds and heat pain. Region of interest analysis revealed that there was significantly lower activation in the right amygdala and in two clusters in the left superior temporal gyrus in the oxytocin administration group compared to the placebo group in response to observing fearful faces. The activation in the conditioned oxytocin group was in between the other two groups for these clusters but did not significantly differ from either group. No group differences were found in the other tasks. Preliminary evidence was found for brain activation of a conditioned oxytocin response; however, despite this trend in the expected direction, the conditioned group did not significantly differ from other groups. Future research should, therefore, investigate the optimal timing of conditioned endocrine responses and study whether the findings generalize to other hormones as well.
已经证明，几种激素的分泌可以进行经典条件作用，然而，这种条件作用的大脑反应从未被研究过。在这项研究中，我们旨在研究催产素的给药和经典条件作用的催产素如何影响大脑反应。总共有 88 名女性被分配到以下三个组之一：催产素给药组、条件化催产素组或安慰剂组，并进行了一个由三个获得期和三个诱发期组成的实验。条件组的参与者在三个获得期内接受 24IU 的催产素和一个条件刺激（CS），并在三个诱发期内接受 CS 和安慰剂。催产素给药组在所有天内接受 24IU 的催产素，安慰剂组在所有天内接受安慰剂。在最后一个诱发期，所有参与者都进行了 fMRI 扫描，在三个先前显示受催产素影响的任务中：呈现情绪面孔、婴儿哭声和热痛。感兴趣区域分析显示，与安慰剂组相比，催产素给药组在观察恐惧面孔时，右侧杏仁核和左侧颞上回的两个簇的激活显著降低。条件化催产素组的激活介于其他两组之间，但与任何一组均无显著差异。在其他任务中没有发现组间差异。有初步证据表明存在条件化催产素反应的大脑激活；然而，尽管存在这种预期方向的趋势，但条件组与其他组没有显著差异。因此，未来的研究应该调查条件内分泌反应的最佳时机，并研究这些发现是否也适用于其他激素。
