Abnormal asymmetry of white matter integrity in schizophrenia revealed by voxelwise diffusion tensor imaging
Abnormal asymmetry of white matter integrity in schizophrenia revealed by voxelwise diffusion tensor imaging
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DOI：
10.1002/hbm.21326
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发表时间：
2012-07-01
影响因子：
4.8
通讯作者：
Murai, Toshiya
中科院分区：
文献类型：
--
作者：
Miyata, Jun;Sasamoto, Akihiko;Murai, Toshiya
许多磁共振成像（MRI）的研究表明，形态皮质不对称在正常的人脑，减少或逆转这种半球不对称已报告精神分裂症。另一方面，弥散张量成像（DTI）研究报告了不一致的结果，关于精神分裂症的白色物质完整性的异常不对称。我们的目的是确认精神分裂症患者全脑白色物质完整性是否存在减少或倒置的不对称性。在这项研究中，26名右利手精神分裂症患者和32名匹配的健康对照者进行了调查。DTI数据的体素分析使用基于道的空间统计学。将分数各向异性（FA）图像归一化并投影到对称的白色骨骼上，并计算FA的偏侧指数（LI），由2 x（左-右）/（左+右）确定。结果表明，精神分裂症患者和健康对照组表现出相似的模式的整体FA不对称。在组间比较中，患者外囊（EC）和内囊后肢（PLIC）的LI显著降低。EC簇显示增加的不对称性，PLIC簇显示减少的不对称性。EC群中FA的右移与阴性症状的严重程度相关。考虑到EC簇包括钩状束和下枕额束，它们与眶额皮质有联系，精神分裂症中白色物质完整性的异常不对称可能通过改变与眶额皮质的连接在精神分裂症的发病机制中起关键作用。^Brain Mapp，2011. (C)2011 Wiley-Liss，Inc.
A number of magnetic resonance imaging (MRI) studies have revealed morphological cortical asymmetry in the normal human brain, and reduction or inversion of such hemispheric asymmetry has been reported in schizophrenia. On the other hand, diffusion tensor imaging (DTI) studies have reported inconsistent findings concerning abnormal asymmetry of white matter integrity in schizophrenia. Our aim was to confirm whether there is reduced or inverted asymmetry of white matter integrity in the whole brain in schizophrenia. For this study, 26 right-handed schizophrenia patients, and 32 matched healthy control subjects were investigated. Voxelwise analysis of DTI data was performed using the tract-based spatial statistics. The fractional anisotropy (FA) images were normalized and projected onto the symmetrical white matter skeleton, and the laterality index (LI) of FA, determined by 2 x (left - right)/(left + right), was calculated. The results reveal that schizophrenia patients and healthy controls showed similar patterns of overall FA asymmetries. In the group comparison, patients showed significant reduction of LI in the external capsule (EC), and posterior limb of the internal capsule (PLIC). The EC cluster revealed increased rightward asymmetry, and the PLIC cluster showed reduced leftward asymmetry. Rightward-shift of FA in the EC cluster correlated with negative symptom severity. Considering that the EC cluster includes the uncinate and inferior occipitofrontal fasciculi, which have connections to the orbitofrontal cortex, abnormal asymmetry of white matter integrity in schizophrenia may play a crucial role in the pathogenesis of schizophrenia, through the altered connectivity to the orbitofrontal cortex. Hum Brain Mapp, 2011. (C) 2011 Wiley-Liss, Inc.