Reduced activation of posterior cingulate cortex during imagery in subjects with high degrees of alexithymia: A functional magnetic resonance imaging study
Reduced activation of posterior cingulate cortex during imagery in subjects with high degrees of alexithymia: A functional magnetic resonance imaging study
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DOI：
10.1016/j.biopsych.2005.01.047
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发表时间：
2005-05-01
影响因子：
10.6
通讯作者：
Yamawaki, S
中科院分区：
文献类型：
--
作者：
Mantani, T;Okamoto, Y;Yamawaki, S
背景：虽然有关表象的脑区已有报道，但表象个体差异的神经基础仍有待阐明。众所周知，高度述情障碍(HDA)的人具有受限的想象能力。方法：根据多伦多述情障碍量表(TAS-20)的20项评分，对10名HDA患者和10名轻度述情障碍(LDA)患者进行功能磁共振成像(FMRI)检查。比较两组受试者在不同表象条件下的局部脑激活情况。在这些条件下，受试者想象一个过去的快乐(PH)事件、一个过去的悲伤(PS)事件、一个过去的中性(PN)事件、一个未来的快乐(FH)事件、一个未来的悲伤(FS)事件。以及未来的中立(FN)事件。结果：经t检验，在PS和FS两种表象条件下，LDA受试者在表象生动程度和表象时情绪强度的平均主观评分均高于HDA受试者。在另一个频段上，相对于LDA组，在PH和FH表象条件下，HDA组大鼠后扣带回(PCC)的激活程度明显低于静息状态和FN表象条件。结论：HDA与快乐表象条件下后扣带回PCC的激活减少有关。鉴于这一大脑区域的功能，这些结果可能与HDA受试者在快乐图像中情景记忆提取的功能障碍有关。
Background: Although the brain areas involved in imagery have been reported, the neural bases of individual differences in imagery remain to be elucidated. People with high degrees of alexithymia (HDA) are known to have constricted imaginal capacities. The purpose of this study was to investigate neural correlates of imagery disturbance in subjects with HDA.Methods: A functional magnetic resonance imaging (fMRI) study was undertaken in 10 subjects with HDA and 10 subjects with low degrees of alexithymia (LDA), who were selected according to their scores on the 20-item Toronto Alexithymia Scale (TAS-20). The two groups' regional cerebral activation was compared during various imagery conditions. in those conditions, the subjects imaged a past happy (PH) event, a past sad (PS) event, a past neutral (PN) event, a future happy (FH) event, a future sad (FS) event. and a future neutral (FN) event. The activation levels during these conditions were compared with those during a rest condition (REST).Results: The t tests showed that the mean subjective ratings of both the vividness of the imagery and the intensiiy of emotion during the imagery were higher in the subjects with LDA than in those with HDA for the PS and FS imagery conditions. On the other band, relative to the LDA group, the HDA group showed significantly less activation in the posterior cingulate cortex (PCC) during the PH and FH imagery conditions compared with REST and during the FH imagery condition compared with the FN imagery condition.Conclusion: The present results suggest an association between an HDA and reduced activation of the PCC during happy imagery. Given the function of this brain region, these results might be related to a dysfunction of episodic memory retrieval during happy imagery in subjects with HDA.