Department of Psychiatry, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Neuroimage Clin. 2022;35:103122. doi: 10.1016/j.nicl.2022.103122. Epub 2022 Jul 19.
Intracortical myelin is involved in speeding and synchronizing neural activity of the cerebral cortex and has been found to be disrupted in various psychiatric disorders. However, its role in obsessive-compulsive disorder (OCD) has remained unknown. In this study, we investigated the alterations in intracortical myelin and their association with white matter (WM) microstructural abnormalities in OCD. T1-weighted and diffusion-weighted brain images were obtained for 51 medication-naïve patients with OCD and 26 healthy controls (HCs). The grey/white matter contrast (GWC) was calculated from T1-weighted signal intensities to characterize the intracortical myelin profile in OCD. Diffusion parameters, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD), were extracted from diffusion-weighted images to examine the WM microstructure in OCD. Compared with HCs, patients with OCD showed increased GWC in the bilateral orbitofrontal, cuneus, lingual and fusiform gyrus, left anterior cingulate, left superior parietal, right inferior parietal, and right middle frontal cortices, suggesting reduced intracortical myelin. Patients with OCD also showed decreased FA in several WM regions, with a topology corresponding to the GWC alterations. In both groups, the mean GWC of the significant clusters in between-group GWC analysis was correlated negatively with the mean FA of the significant clusters in between-group FA analysis. In patients with OCD, the FA of a cluster in the right cerebellum correlated negatively with the Yale-Brown obsessive-compulsive scale scores. Our results suggest that abnormal intracortical and WM myelination could be the microstructural basis for the brain connectivity alterations and disrupted inhibitory control in OCD.
脑皮质内的髓鞘参与了加速和同步大脑皮质的神经活动，并且已经在各种精神疾病中发现其被破坏。然而，其在强迫症（OCD）中的作用仍不清楚。在这项研究中，我们研究了 OCD 中脑皮质内髓鞘的改变及其与白质（WM）微观结构异常的关系。为 51 名未经药物治疗的 OCD 患者和 26 名健康对照（HC）获得了 T1 加权和弥散加权脑图像。从 T1 加权信号强度计算灰质/白质对比（GWC），以描述 OCD 中的脑皮质内髓鞘轮廓。从弥散加权图像中提取弥散参数，包括各向异性分数（FA）、平均弥散度（MD）、轴向弥散度（AD）和径向弥散度（RD），以检查 OCD 中的 WM 微观结构。与 HCs 相比，OCD 患者双侧眶额回、楔前叶、舌回和梭状回、左前扣带回、左顶上回、右顶下回和右中额叶皮质的 GWC 增加，提示脑皮质内髓鞘减少。OCD 患者还显示出几个 WM 区域的 FA 降低，拓扑结构与 GWC 改变相对应。在两组中，组间 GWC 分析中显著簇的平均 GWC 与组间 FA 分析中显著簇的平均 FA 呈负相关。在 OCD 患者中，小脑右侧一个簇的 FA 与耶鲁-布朗强迫症量表评分呈负相关。我们的结果表明，异常的脑皮质内和 WM 髓鞘可能是 OCD 中大脑连接改变和抑制控制中断的微观结构基础。
