Preis Mira A, Kröner-Herwig Birgit, Schmidt-Samoa Carsten, Dechent Peter, Barke Antonia
Georg-August University of Goettingen, Georg-Elias-Mueller Institute of Psychology, Department of Clinical Psychology and Psychotherapy, Goßlerstraße 14, 37073, Goettingen, Germany.
University Medical Center Goettingen, Department of Cognitive Neurology, MR Research in Neurology and Psychiatry, Robert-Koch-Straße 40, 37075, Göttingen, Germany.
PLoS One. 2015 Aug 28;10(8):e0137056. doi: 10.1371/journal.pone.0137056. eCollection 2015.
Neuroimaging studies have demonstrated that the actual experience of pain and the perception of another person in pain share common neural substrates, including the bilateral anterior insular cortex and the anterior midcingulate cortex. As many fMRI studies include the exposure of participants to repeated, similar stimuli, we examined whether empathic neural responses were affected by habituation and whether the participants' prior pain experience influenced these habituation effects.
In 128 trials (four runs), 62 participants (31 women, 23.0 ± 4.2 years) were shown pictures of hands exposed to painful pressure (pain pictures) and unexposed (neutral pictures). After each trial, the participants rated the pain of the model. Prior to the experiment, participants were either exposed to the same pain stimulus (pain exposure group) or not (touch exposure group). In order to assess possible habituation effects, linear changes in the strength of the BOLD response to the pain pictures (relative to the neutral pictures) and in the ratings of the model's pain were evaluated across the four runs.
Although the ratings of the model's pain remained constant over time, we found neural habituation in the bilateral anterior/midinsular cortex, the posterior midcingulate extending to dorsal posterior cingulate cortex, the supplementary motor area, the cerebellum, the right inferior parietal lobule, and the left superior frontal gyrus, stretching to the pregenual anterior cingulate cortex. The participant's prior pain experience did neither affect their ratings of the model's pain nor their maintenance of BOLD activity in areas associated with empathy. Interestingly, participants with high trait personal distress and fantasy tended to show less habituation in the anterior insula.
Neural structures showed a decrease of the BOLD signal, indicating habituation over the course of 45 minutes. This can be interpreted as a neuronal mechanism responding to the repeated exposure to pain depictions, which may be regarded as functional in a range of contexts.
神经影像学研究表明，实际的疼痛体验与对他人疼痛的感知共享共同的神经基质，包括双侧前脑岛皮质和前扣带回中部皮质。由于许多功能磁共振成像（fMRI）研究让参与者暴露于重复、相似的刺激下，我们研究了共情神经反应是否受习惯化影响，以及参与者先前的疼痛经历是否会影响这些习惯化效应。
在128次试验（四个序列）中，向62名参与者（31名女性，23.0±4.2岁）展示遭受疼痛压力的手部图片（疼痛图片）和未遭受疼痛压力的手部图片（中性图片）。每次试验后，参与者对模型的疼痛程度进行评分。实验前，参与者要么暴露于相同的疼痛刺激下（疼痛暴露组），要么未暴露于疼痛刺激下（触摸暴露组）。为了评估可能的习惯化效应，在四个序列中评估了对疼痛图片（相对于中性图片）的血氧水平依赖（BOLD）反应强度和模型疼痛评分的线性变化。
尽管模型疼痛评分随时间保持不变，但我们发现双侧前/中脑岛皮质、延伸至背侧后扣带回皮质的后扣带回中部、辅助运动区、小脑、右侧下顶叶小叶和左侧额上回（延伸至膝前扣带回皮质）存在神经习惯化。参与者先前的疼痛经历既不影响他们对模型疼痛的评分，也不影响与共情相关区域的BOLD活动维持。有趣的是，具有高特质性个人痛苦和幻想倾向的参与者在前脑岛的习惯化程度往往较低。
神经结构显示BOLD信号降低，表明在45分钟内出现了习惯化。这可以解释为一种神经元机制，对重复暴露于疼痛描绘做出反应，在一系列情境中可能具有功能性。
