Department of Psychology, University of Haifa, Mount Carmel, Haifa, Israel.
Hum Brain Mapp. 2010 Feb;31(2):326-38. doi: 10.1002/hbm.20867.
Anxiety arising during pain expectancy can modulate the subjective experience of pain. However, individuals differ in their sensitivity to pain expectancy. The amygdale and hippocampus were proposed to mediate the behavioral response to aversive stimuli. However, their differential role in mediating anxiety-related individual differences is not clear. Using fMRI, we investigated brain activity during expectancy to cued or uncued thermal pain applied to the wrist. Following each stimulation participants rated the intensity of the painful experience. Activations in the amygdala and hippocampus were examined with respect to individual differences in harm avoidance (HA) personality trait, and individual sensitivity to expectancy, (i.e. response to cued vs. uncued painful stimuli). Only half of the subjects reported on cued pain as being more painful than uncued pain. In addition, we found a different activation profile for the amygdala and hippocampus during pain expectancy and experience. The amygdala was more active during expectancy and this activity was correlated with HA scores. The hippocampal activity was equally increased during both pain expectancy and experience, and correlated with the individual's sensitivity to expectancy. Our findings suggest that the amygdala supports an innate tendency to approach or avoid pain as reflected in HA trait, whereas the hippocampus mediates the effect of context possibly via appraisal of the stimulus value.
在预期疼痛时产生的焦虑可以调节疼痛的主观体验。然而，个体对疼痛预期的敏感性存在差异。杏仁核和海马体被认为介导对厌恶刺激的行为反应。然而，它们在介导与焦虑相关的个体差异方面的差异作用尚不清楚。使用 fMRI，我们研究了在腕部给予提示或非提示性热刺激时预期期间的大脑活动。每次刺激后，参与者都会对疼痛体验的强度进行评分。检查了杏仁核和海马体的激活情况，以了解回避性人格特质（HA）的个体差异，以及对预期的个体敏感性（即对提示性与非提示性疼痛刺激的反应）。只有一半的受试者报告说，提示性疼痛比非提示性疼痛更痛。此外，我们还发现了在疼痛预期和体验期间杏仁核和海马体的不同激活模式。杏仁核在预期期间更活跃，这种活动与 HA 评分相关。海马体在疼痛预期和体验期间的活动同样增加，并与个体对预期的敏感性相关。我们的研究结果表明，杏仁核支持一种接近或回避疼痛的先天倾向，这种倾向反映在 HA 特质中，而海马体可能通过评估刺激价值来介导预期的影响。
