非注意条件下抑郁症患者和健康个体对情绪词加工的不同脑激活模式

目的 探讨在非注意状态下,抑郁症患者与健康个体对情绪词的大脑加工模式,检验抑郁症与"对积极刺激加工的减弱和对消极刺激加工的增强"有关的理论假设.方法 8例抑郁症患者和8名健康个体参加了试验,刺激呈现时积极、消极和中性词被掩蔽,要求被试对掩蔽符号进行知觉判断.采用事件相关的脑功能磁共振成像技术,用2.0 T GE Prestige全身MRI扫描仪进行脑功能活动的数据采集,应用SPM2软件包进行数据处理.结果 积极词与中性词相比,抑郁症患者没有表现出任何脑区的激活,而健康个体则激活了右侧眶额、右侧前扣带回、右侧丘脑和双侧尾状核等多个与积极情绪加工有关的脑区;消极词与中性词相比,抑郁症患者激活了左侧壳核和左外侧苍白球两个皮下区域,健康个体则激活了脑岛.结论结果支持抑郁症患者对积极信息加工能力受损的假设.本研究从非注意加工的角度进一步揭示 了抑郁症患者消极认知偏向和社会功能失调的认知神经机制.

Different activation pattern to unattended emotional words in depressed vs.healthy subjects

Objective Depression is thought to be related with either diminished processing of positive stimuli or enhanced processing of negative stimuli.Method Eight depressed patients and 8 healthy controls were required to make a perceptual judgment on two figures representing the backward masks of positive,neutral,or negative words. 2.0 T GE Prestige MRI system was used to collect the fMRI data that were post-processed with the software Statistical Parametric Mapping(SPM2).Results For positive words contrary to neutral words.the depressed subjects exhibited no activation,while the controls showed activation in the right orbitofrontal cortex,right anterior cingulate gyrus,right thalamus,and bilateral caudate that are implicated in the processing of positive emotion.For the negative words vs.neutral words,the depressed subjects showed activation in the left putamen and left lateral globus pallidus,while the controls only showed activation in the insular cortex. No significant difference was found in both positive and negative(relative to neutral)words between the depressed participants and controls. Conclusion These results support the hypothesis that depressed patients are impaired in the processing of positive information.The activation pattern may suggest the neural mechanism underlying the negative bias and social dysfunction in clinical depression under unattended processing.