首发抑郁症患者空间工作记忆的fMRI研究

Neural Dysfunction of Spatial Working Memory in the First-episode Depression by Functional MRI

目的:探讨首发抑郁症患者矩阵工作记忆任务的脑功能磁共振成像(fMRI)激活特征,为抑郁症空间工作记忆力的缺损机制提供影像学线索。材料和方法:12例首发抑郁症患者与12例健康对照者,配对进行矩阵工作记忆任务的脑fMRI扫描。以AFNI软件对fMRI数据定位定量分析。结果:①首发抑郁症患者组矩阵工作记忆0-back及2-back任务执行正确率均低于对照组(P<0.05);②矩阵工作记忆任务激活两组受试者的脑区为:右侧与左侧前额叶BA9/46、右侧与左侧顶叶BA7/40、右侧与左侧额叶BA6区及辅助运动区SMA(P<0.05);③患者组的上述前六个脑区激活强度分别为:0.21%、1.11%、2.61%、2.82%、1.23%与1.31%,低于对照组的2.60%、2.50%、4.96%、4.36%、2.94%与3.45%(P<0.05)。两组间SMA区激活差异无统计学意义(P>0.05)。结论:首发抑郁症患者矩阵空间工作记忆能力下降,双侧BA9/46、BA6与BA7/40区功能减弱是其空间工作记忆能力缺损的机制之一。

Purpose： To explore the abnormal brain activity associated with spatial working memory in first - episode depression by functional MRI.Materials and Methods. Twelve patients with first - episode depressive disorder and 12 healthy controls were tested with a spatial version of the n - back task during fMRI scanning. The working memory load was manipulated across the experiment （0, 2- back）. fMRI data were analyzed using AFNI software. Results： Significantly lower accuracy was found for the 0, 2- back task in depressive participants（ P 〈 0.05）. The activated ROI included bilateral BA9/46, BA7/ 40, BA6 and SMA（P 〈 0.05）. The signal change of depressive participants showed 0.21, 1.11, 2.61, 2.82, 1.23 and 1.31（ 96 ） in right BA9/46, left BA9/46, right BA7/40, left BA7/40, right BA6 and left BA6, all lower than health control（P 〈 0.05） . There is no difference of signal change in SMA between the two groups（ P 〉 0.05）. Conclusion： These results indicate the existence of an abnormal network of prefrontal and parietal regions mediating the impairments of spatial working memory in first episode depression.