Department of Psychology, University of Greifswald, Greifswald, Germany.
Psychophysiology. 2012 Oct;49(10):1319-29. doi: 10.1111/j.1469-8986.2012.01451.x. Epub 2012 Aug 22.
Repetitive exposure to feared stimuli is considered as the essential element in therapy with phobic patients. However, the mechanisms mediating symptom reduction and their underlying neurobiological processes are poorly understood. Therefore, we presented the same fear-relevant and neutral stimuli repeatedly to individuals with high and low fear of animals during fMRI scanning. High-, but not low-fearful individuals showed an initial fear-stimulus-related potentiation of amygdala and insula activity. Potentiation of the amygdala in the high-fearful group habituated quickly, but insula activity was still potentiated during later repetition trials. Both groups showed an initial potentiation of the dorsomedial prefrontal cortex (dmPFC) that continuously decreased in low-, but not in high-fearful participants. Thus, within-session habituation may occur on an automatic processing level (amygdala), but does not cause lasting neural changes on a higher order cortical level (dmPFC).
反复暴露于恐惧刺激被认为是恐惧症患者治疗的重要因素。然而，介导症状减轻的机制及其潜在的神经生物学过程还知之甚少。因此，我们在 fMRI 扫描期间向高恐惧和低恐惧动物的个体反复呈现相同的与恐惧相关的和中性的刺激。高恐惧但不是低恐惧的个体表现出杏仁核和岛叶活动的初始恐惧刺激相关增强。高恐惧组的杏仁核增强迅速习惯化，但岛叶活动在后续重复试验中仍被增强。两组都表现出背内侧前额叶皮层 (dmPFC) 的初始增强，在低恐惧但不是高恐惧参与者中持续降低。因此，在一个会话内的习惯化可能发生在自动处理水平（杏仁核）上，但不会导致在更高阶皮质水平（dmPFC）上的持久的神经变化。
