Forkmann Katarina, Wiech Katja, Sommer Tobias, Bingel Ulrike
Department of Neurology, Essen University Hospital, Essen, Germany FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Pain. 2015 Aug;156(8):1501-1510. doi: 10.1097/j.pain.0000000000000194.
Remembering an event partially reactivates cortical and subcortical brain regions that were engaged during its experience and encoding. Such reinstatement of neuronal activation has been observed in different sensory systems, including the visual, auditory, olfactory, and somatosensory domain. However, so far, this phenomenon of incidental memory has not been explored in the context of pain. In this functional magnetic resonance imaging study, we investigated the neural reinstatement of pain-related and tone-related activations during the recognition of neutral images that had been encoded during (1) painful stimulation, (2) auditory stimulation of comparable unpleasantness, or (3) no additional stimulation. Stimulus-specific reinstatement was tested in 24 healthy male and female participants who performed a visual categorization task (encoding) that was immediately followed by a surprise recognition task. Neural responses were acquired in both sessions. Our data show a partial reinstatement of brain regions frequently associated with pain processing, including the left posterior insula, bilateral putamen, and right operculum, during the presentation of images previously paired with painful heat. This effect was specific to painful stimuli. Moreover, the bilateral ventral striatum showed stronger responses for remembered pain-associated images as compared with tone-associated images, suggesting a higher behavioral relevance of remembering neutral pictures previously paired with pain. Our results support the biological relevance of pain in that only painful but not equally unpleasant auditory stimuli were able to "tag" neutral images during their simultaneous presentation and reactivate pain-related brain regions. Such mechanisms might contribute to the development or maintenance of chronic pain and deserve further investigation in clinical populations.
回忆一个事件会部分重新激活在经历和编码该事件时参与的皮质和皮质下脑区。这种神经元激活的恢复在不同的感觉系统中都有观察到，包括视觉、听觉、嗅觉和躯体感觉领域。然而，到目前为止，这种偶然记忆现象尚未在疼痛背景下进行探索。在这项功能磁共振成像研究中，我们调查了在识别在（1）疼痛刺激、（2）具有相当不愉快程度的听觉刺激或（3）无额外刺激期间编码的中性图像时，与疼痛相关和与音调相关的激活的神经恢复情况。在24名健康男性和女性参与者中测试了刺激特异性恢复，这些参与者执行了一个视觉分类任务（编码），随后立即进行了一个意外识别任务。在两个阶段都采集了神经反应。我们的数据显示，在呈现先前与疼痛性热配对的图像时，经常与疼痛处理相关的脑区，包括左后岛叶、双侧壳核和右额下回，出现了部分恢复。这种效应是疼痛刺激特有的。此外，与音调相关的图像相比，双侧腹侧纹状体对记忆中与疼痛相关的图像表现出更强的反应，这表明记住先前与疼痛配对的中性图片具有更高的行为相关性。我们的结果支持了疼痛的生物学相关性，即只有疼痛但不是同样不愉快的听觉刺激能够在同时呈现时“标记”中性图像并重新激活与疼痛相关的脑区。这种机制可能有助于慢性疼痛的发展或维持，值得在临床人群中进一步研究。
