单相和双相抑郁障碍患者前扣带回功能连接特征差异观察

Observation on the resting-state fMRI functional connectivity of the anterior cingulate cortex in unipolar and bipolar depression

目的比较单、双相抑郁障碍前扣带回功能连接的差异,探讨前扣带回功能连接与抑郁症状严重程度的关系。方法利用fMRI技术,对符合DSM-Ⅳ诊断标准的30例单相抑郁障碍(unipolar depression)患者(单相抑郁组)、30例双相抑郁障碍(bipolar depression)患者(双相抑郁组)及年龄、性别、受教育程度相匹配的32名对照者(对照组)进行静息态fMRI扫描,以前扣带回为感兴趣区进行功能连接分析,比较组间差异,并对功能连接强度与抑郁症状的严重程度之间的关联进行Pearson相关分析。结果(1)与对照组相比,单相抑郁组左侧前扣带回与左侧三角部额下回(t=3.48)、左侧顶下缘角回(t=3.15)之间的功能连接增强,右侧前扣带回与左侧三角部额下回(t=3.52)之间的功能连接增强;(2)与对照组相比,双相抑郁组左侧前扣带回与右侧颞中回(t=-4.00)之间的功能连接减低,右侧前扣带回与左侧中央后回(t=-3.46)、右侧颞上回(t=-2.86)、右侧颞中回(t=-3.40)之间的功能连接减低;(3)与双相抑郁组相比,单相抑郁组左侧前扣带回与左侧三角部额下回(t=3.58)、右侧三角部额下回(t=4.06)、右侧颞中回(t=3.25)、左侧顶下缘角回(t=3.27)、右侧顶下缘角回(t=3.99)之间的功能连接增强;右侧前扣带回与左侧三角部额下回(t=3.13)、左侧顶下缘角回(t=3.42)、右侧顶下缘角回(t=3.78)之间的功能连接增强(均采用Alphasim校正,P<0.001);(4)Pearson相关分析显示,以上差异脑区功能连接强度与HAMD17总分均无相关性(-0.2<r<0.2,P>0.05)。结论静息态下单相抑郁患者前扣带回功能连接增强,双相抑郁患者前扣带回功能连接减弱;单、双相抑郁障碍差异脑区功能连接强度与临床症状无相关性。

Objective To investigate the functional connection(FC) between the anterior cingulate cortex (ACC) and other brain regions in unipolar depression(UD) and bipolar depression(BD), and the correlation to the severity of depressive symptoms. Methods 30 patients who met the diagnosis criteria of unipolar depression in DSM-Ⅳ and another 30 patients who met the diagnosis criteria of bipolar depression in DSM-Ⅳ were matched with 32 healthy controls(HC) by gender-, age-, and education. All subjects completed the resting-state functional magnetic resonance scans. After the imaging preprocessing, seed-based functional connectivity analysis was performed on the bilateral ACC. Pearson correlation analysis was performed between the FC values and the severity of depressive symptoms (measured by HAMD17 scores). Results (1) Compared to the health controls, the connectivity between the left ACC (LACC) and the left triangular part of the inferior frontal gyrus(t=3.48) and the connectivity from the LACC to the left inferior parietal gyrus(t=3.15) in patients with unipolar depression significantly increased, so did the connectivity between the right ACC(RACC) and the left triangular part of the inferior frontal gyrus(t=3.52);(2) Compared to the healthy controls, the connectivity from LACC to the right middle temporal gyrus(t=-4.00) in patients with bipolar depression significantly decreased, so did the connectivity between RACC and the other regions induding the left postcentral(t=-3.46), the right superior temporal gyrus(t=-2.86) and the right middle temporal gyrus(t=-3.40);(3)Compared to the patients with bipolar depression, patients with unipolar depression increased connectivity between the LACC and the other regions including the left triangular part of the inferior frontal gyrus(t=3.58), the right triangular part of the inferior frontal gyrus(t=4.06), the right middle temporal gyrus (t=3.25), the left inferior parietal gyrus(t=3.27), and the right inferior parietal gyrus(t=3.99). While the RACC increased its connectivity to the left triangular part of the inferior frontal gyrus(t=3.13), the left inferior parietal gyrus(t=3.42), and the right inferior parietal gyrus(t=3.78)(Alphasim-corr, P<0.001);(4) The severity of depressive symptoms were found uncorrelated to the FC value changes among the different regions (-0.2<r<0.2, P>0.05). Conclusion The results suggest that there are much difference in the brain function activity between UD and BD. The connectivity between ACC and other regions is stronger in UD patients, while weaker in BD patients, therefore the FC value could be possibly explored as an independent future biomarker to distinguish BD from UD regardless the symptoms severity.