Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.
ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal.
Transl Psychiatry. 2017 Aug 29;7(8):e1224. doi: 10.1038/tp.2017.189.
Obsessive-compulsive disorder (OCD) is one of the most debilitating psychiatric conditions. An extensive body of the literature has described some of the neurobiological mechanisms underlying the core manifestations of the disorder. Nevertheless, most reports have focused on individual modalities of structural/functional brain alterations, mainly through targeted approaches, thus possibly precluding the power of unbiased exploratory approaches. Eighty subjects (40 OCD and 40 healthy controls) participated in a multimodal magnetic resonance imaging (MRI) investigation, integrating structural and functional data. Voxel-based morphometry analysis was conducted to compare between-group volumetric differences. The whole-brain functional connectome, derived from resting-state functional connectivity (FC), was analyzed with the network-based statistic methodology. Results from structural and functional analysis were integrated in mediation models. OCD patients revealed volumetric reductions in the right superior temporal sulcus. Patients had significantly decreased FC in two distinct subnetworks: the first, involving the orbitofrontal cortex, temporal poles and the subgenual anterior cingulate cortex; the second, comprising the lingual and postcentral gyri. On the opposite, a network formed by connections between thalamic and occipital regions had significantly increased FC in patients. Integrative models revealed direct and indirect associations between volumetric alterations and FC networks. This study suggests that OCD patients display alterations in brain structure and FC, involving complex networks of brain regions. Furthermore, we provided evidence for direct and indirect associations between structural and functional alterations representing complex patterns of interactions between separate brain regions, which may be of upmost relevance for explaining the pathophysiology of the disorder.
强迫症（OCD）是最具致残性的精神疾病之一。大量文献描述了该疾病核心表现背后的一些神经生物学机制。然而，大多数报告都集中在结构/功能脑改变的个别模态上，主要通过靶向方法，因此可能排除了无偏探索方法的力量。80 名受试者（40 名强迫症患者和 40 名健康对照者）参与了一项多模态磁共振成像（MRI）研究，整合了结构和功能数据。进行基于体素的形态计量学分析，以比较组间体积差异。从静息态功能连接（FC）得出的全脑功能连接组被分析采用网络统计方法。结构和功能分析的结果整合在中介模型中。强迫症患者右侧颞上回体积减小。患者在两个不同的子网络中存在明显的 FC 降低：第一个子网络包括眶额皮质、颞极和扣带回前下部；第二个子网络包括舌回和后中央回。相反，患者丘脑和枕叶之间的连接形成的网络 FC 显著增加。综合模型显示，体积改变与 FC 网络之间存在直接和间接的关联。这项研究表明，强迫症患者的大脑结构和 FC 存在改变，涉及到大脑区域的复杂网络。此外，我们提供了结构和功能改变之间直接和间接关联的证据，代表了不同大脑区域之间相互作用的复杂模式，这可能对解释该疾病的病理生理学至关重要。
