Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, PA, USA.
Department of Radiology, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, PA, USA.
Neuropsychopharmacology. 2019 Jun;44(7):1182-1188. doi: 10.1038/s41386-019-0353-4. Epub 2019 Feb 25.
Obsessive-compulsive disorder (OCD) is a disabling condition, often associated with a chronic course. Given its role in attentional control, decision-making, and emotional regulation, the anterior cingulate cortex is considered to have a key role in the pathophysiology of the disorder. Notably, the cingulum bundle, being the major white matter tract connecting to this region, has been historically a target for the surgical treatment of intractable OCD. In this study, we aimed to identify the extent to which focal-more than diffuse-abnormalities in fiber collinearity of the cingulum bundle could distinguish 48 adults with OCD (mean age [SD] = 23.3 [4.5] years; F/M = 30/18) from 45 age- and sex-matched healthy control adults (CONT; mean age [SD] = 23.2 [3.8] years; F/M = 28/17) and further examine if these abnormalities correlated with symptom severity. Use of tract-profiles rather than a conventional diffusion imaging approach allowed us to characterize white matter microstructural properties along (100 segments), as opposed to averaging these measures across, the entire tract. To account for these 100 different segments of the cingulum bundle, a repeated measures analysis of variance revealed a main effect of group (OCD < CONT; F = 5.3; P = 0.024) upon fractional anisotropy (FA, a measure of fiber collinearity and/or white matter integrity), in the cingulum bundle, bilaterally. Further analyses revealed that these abnormalities were focal (middle portion) within the left and right cingulum bundle, although did not correlate with symptom severity in OCD. Findings indicate that focal abnormalities in connectivity between the anterior cingulate cortex and other prefrontal cortical regions may represent neural mechanisms of OCD.
强迫症（OCD）是一种使人丧失能力的疾病，通常与慢性病程有关。鉴于其在注意力控制、决策和情绪调节中的作用，前扣带皮层被认为在该疾病的病理生理学中起着关键作用。值得注意的是，扣带束作为连接该区域的主要白质束，历来是治疗难治性 OCD 的手术目标。在这项研究中，我们旨在确定前扣带皮层与其他前额叶皮质区域之间连接的纤维连贯性的局灶性（而非弥漫性）异常在多大程度上可以区分 48 名 OCD 成人（平均年龄 [标准差] = 23.3 [4.5] 岁；男/女 = 30/18）和 45 名年龄和性别匹配的健康对照成年人（CONT；平均年龄 [标准差] = 23.2 [3.8] 岁；男/女 = 28/17），并进一步研究这些异常是否与症状严重程度相关。使用束状轮廓而不是常规的扩散成像方法，使我们能够沿着（100 个节段）而不是在整个束上平均这些测量值来描绘白质微观结构特性。为了考虑到扣带束的这 100 个不同节段，重复测量方差分析显示，在扣带束中，组间存在主要的组间效应（OCD < CONT；F = 5.3；P = 0.024），这反映在各向异性分数（FA，一种衡量纤维连贯性和/或白质完整性的指标）上。进一步的分析表明，这些异常是局灶性的（左、右扣带束的中部），尽管与 OCD 中的症状严重程度无关。研究结果表明，前扣带皮层与其他前额叶皮质区域之间连接的连接异常可能代表 OCD 的神经机制。
