Ran Shuhua, Zuo Zhiwei, Li Chang, Yin Xuntao, Qu Wei, Tang Qianying, Wang Yao, Shi Yanshu, Li Haitao
Department of Radiology, Southwest Hospital, Army Medical University, Chongqing, People's Republic of China.
Department of Radiology, General Hospital of Western Theater Command, Chengdu, People's Republic of China.
Neuropsychiatr Dis Treat. 2020 Jun 10;16:1473-1482. doi: 10.2147/NDT.S245078. eCollection 2020.
Impairments in intra- and inter-hemispheric information transfer circuits have been reported in patients with major depressive disorder (MDD). However, the specific anomalous connection (intra- and/or inter-hemispheric) and hemisphere (left and/or right) in which this connection plays a more dominant role in the pathogenic mechanism underlying MDD are still poorly understood.
Structural magnetic resonance imaging and resting-state functional magnetic resonance imaging were performed in 33 patients with MDD and 33 healthy controls. The intra- and inter-hemispheric functional connectivity (FC) strength in the default mode network areas and volume of the callosal subregions were computed using independent samples -tests. The partial correlations between the volumes and FCs were also computed.
The patients with MDD had smaller volumes in the genu of the corpus callosum than the controls. The intrahemispheric FCs of the bilateral posterior cingulate gyrus, left precuneus, left medial superior frontal gyrus, left medial orbitofrontal gyrus, left angular gyrus and left middle temporal gyrus, and interhemispheric FCs of the bilateral posterior cingulate gyrus in the patients with MDD were lower than those in the controls. Moreover, the intrahemispheric FCs of the precuneus and interhemispheric FCs of middle frontal gyrus, orbital middle frontal gyrus, and anterior cingulate gyrus in the patients with MDD showed right-lateralized asymmetry, which were opposite from the asymmetry patterns observed in the controls. The functional asymmetry of the anterior cingulate gyrus was correlated with the volume of the genu of the corpus callosum and disease duration.
These findings provide robust evidence that intra- and inter-hemispheric disconnections are involved in MDD, and that functional disruptions in the left hemisphere may be more relevant to the pathophysiology of MDD. Furthermore, imbalanced interhemispheric exchanges may contribute to the anatomical deficits in the corpus callosum in patients with MDD.
已有报道称，重度抑郁症（MDD）患者存在半球内和半球间信息传递回路的损伤。然而，在MDD发病机制中起更主要作用的具体异常连接（半球内和/或半球间）以及半球（左半球和/或右半球）仍知之甚少。
对33例MDD患者和33名健康对照者进行了结构磁共振成像和静息态功能磁共振成像检查。使用独立样本t检验计算默认模式网络区域内的半球内和半球间功能连接（FC）强度以及胼胝体亚区域的体积。还计算了体积与FC之间的偏相关性。
MDD患者胼胝体膝部的体积小于对照组。MDD患者双侧后扣带回、左侧楔前叶、左侧额上回内侧、左侧眶额回内侧、左侧角回和左侧颞中回的半球内FC，以及双侧后扣带回的半球间FC低于对照组。此外，MDD患者楔前叶的半球内FC以及额中回、眶额中回和前扣带回的半球间FC表现为右侧化不对称，这与对照组观察到的不对称模式相反。前扣带回的功能不对称与胼胝体膝部的体积和病程相关。
这些发现提供了有力证据，表明半球内和半球间的连接中断与MDD有关，并且左半球的功能破坏可能与MDD的病理生理学更相关。此外，半球间交换失衡可能导致MDD患者胼胝体的解剖学缺陷。
