Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, Institute for Brain Research and Rehabilitation (IBRR), South China Normal University, Guangzhou 510631, China.
Medical Imaging Center, First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Clinical Experimental Center, First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
Prog Neuropsychopharmacol Biol Psychiatry. 2018 Feb 2;81:340-349. doi: 10.1016/j.pnpbp.2017.09.006. Epub 2017 Sep 11.
Differential brain structural abnormalities between bipolar disorder (BD) and major depressive disorder (MDD) may reflect different pathological mechanisms underlying these two brain disorders. However, few studies have directly compared the brain structural properties, especially in white matter (WM) tracts, between BD and MDD. Using automated fiber-tract quantification (AFQ), we utilized diffusion tensor images (DTI) from 67 unmedicated depressed patients, including 31 BD and 36 MDD, and 45 healthy controls (HC) to create fractional anisotropy (FA) tract profiles along 20 major WM tracts. Then, we compared between-group differences in FA values at each node along the fiber tracts. To differentiate the BD and the MDD, we enrolled the diffusion measures of the tract profiles into support vector machine (SVM), a type of machine learning algorithm. The BD showed lower FA in the insular cortex portion of the right uncinate fasciculus (UF) compared to the MDD and in the prefrontal lobe portion of the right UF compared to the HC. The MDD showed lower FA in the prefrontal lobe portion of the left anterior thalamic radiation (ATR) compared to the HC. Using the SVM approach, we found the FA tract profile of the left ATR can be used to differentiate the BD and the MDD at an accuracy up to 68.33% (p=0.018). These findings suggested that the BD and the MDD may be characterized by different abnormalities in specific segments of brain WM tracts, especially in two frontal-situated tracts, the right UF and the left ATR.
双相障碍 (BD) 和重度抑郁症 (MDD) 之间的大脑结构差异可能反映了这两种脑部疾病的不同病理机制。然而，很少有研究直接比较 BD 和 MDD 之间的大脑结构特征，特别是在白质 (WM) 束上。我们使用自动纤维束定量 (AFQ) 技术，对 67 名未用药的抑郁患者（包括 31 名 BD 和 36 名 MDD）和 45 名健康对照者（HC）的弥散张量图像 (DTI) 进行分析，以构建 20 条主要 WM 束的分数各向异性 (FA) 束图。然后，我们比较了各组纤维束各节点 FA 值的差异。为了区分 BD 和 MDD，我们将纤维束图谱的扩散指标纳入支持向量机（SVM），这是一种机器学习算法。BD 在右侧钩束的岛叶部分的 FA 值较 MDD 低，而在右侧钩束的前额叶部分较 HC 低。MDD 在左侧前丘脑辐射（ATR）的前额叶部分的 FA 值较 HC 低。使用 SVM 方法，我们发现左侧 ATR 的 FA 束图可用于区分 BD 和 MDD，准确率高达 68.33%（p=0.018）。这些发现表明，BD 和 MDD 可能表现为特定 WM 束节段的不同异常，特别是在前额叶位置的两条 WM 束，即右侧 UF 和左侧 ATR。
