精神分裂症患者任务诱发去激活的fMRI研究

Functional MR study of task-induced deactivations in schizophrenic patients

目的:任务诱发去激活(Task induced deactivation,TID)皮层区是静息态脑功能的"默认"模式相关脑区,可能与自我定向思维活动有关。本文探讨精神分裂症患者中线TID脑区是否出现变化,以及TID脑区与患者情感状态、行为学表现间的相关性。材料与方法:15例精神分裂症患者和15例与之匹配的正常对照组执行2-back工作记忆任务时行全脑BOLD-fMRI扫描,对每个受试者进行PANAS量表评定。结果:与正常组比较,患者组2-back任务中反应时间(RT)延长,前额叶内侧皮层(MPFC)、后内侧皮层(PMC)脑区TID效应降低,负性情绪评分增加;患者组MPFC区TID与RT、负性情绪评分呈负相关。结论:精神分裂症患者在认知任务执行中存在着认知-情感之间注意资源转移效率障碍,这可能是精神分裂症患者认知功能障碍的神经机制之一。

Objective： Task-induced deactivations （TIDs） of cortical regions may reflect elements of a ＂default-mode＂ of brain function associated with self-directed mental processes at rest. TID phenomenon in schizophrenia and its relevance to patients＇ emotional state and task performance were examined. Materials and Methods： Fifteen schizophrenic patients and matched control subjects were studied in a fMRI design of 2-back working memory task. Positive and negative affect scale scores were calculated for every individuals. Results： Relative to control subjects, patients showed significantly prolonged reaction time, lower TID of the medial prefrontal cortex and posterior medial cortex, and higher negative emotional scores. The magnitude of the TID for medial prefrontal cortex was associated negatively with patients＇ reaction time and negative emotional scale. Conclusion： Shift efficiency of attention resource between cognitive and emotional state is impaired, which is probably one of the neural mechanism of cognitive function impairment for schizophrenic patients.