Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.
J Affect Disord. 2023 Oct 1;338:220-227. doi: 10.1016/j.jad.2023.06.012. Epub 2023 Jun 9.
The recent widespread use of diffusion tensor imaging (DTI) tractography allowed researchers to investigate the diffusivity modifications and neuroanatomical changes of white matter (WM) fascicles in major psychiatric disorders, including bipolar disorder (BD). In BD, corpus callosum (CC) seems to have a crucial role in explaining the pathophysiology and cognitive impairment of this psychiatric disorder. This review aims to provide an overview on the latest results emerging from studies that investigated neuroanatomical changes of CC in BD using DTI tractography.
Bibliographic research was conducted on PubMed, Scopus and Web of Science datasets until March 2022. Ten studies fulfilled our inclusion criteria.
From the reviewed DTI tractography studies a significant decrease of fractional anisotropy emerged in the genu, body and splenium of CC of BD patients compared to controls. This finding is coupled with reduction of fiber density and modification in fiber tract length. Finally, an increase of radial and mean diffusivity in forceps minor and in the entire CC was also reported.
Small sample size, heterogeneity in terms of methodological (diffusion gradient) and clinical (lifetime comorbidity, BD status, pharmacological treatments) characteristics.
Overall, these findings suggest the presence of structural modifications in CC in BD patients, which may in turn explain the cognitive impairments often observed in this psychiatric disorder, especially in executive processing, motor control and visual memory. Finally, structural modifications may suggest an impairment in the amount of functional information and a morphological impact within those brain regions connected by CC.
弥散张量成像（DTI）技术的广泛应用，使研究人员能够研究包括双相障碍（BD）在内的主要精神疾病的白质（WM）束的弥散性改变和神经解剖学变化。在 BD 中，胼胝体（CC）似乎在解释这种精神疾病的病理生理学和认知障碍方面起着关键作用。本综述旨在概述使用 DTI 束追踪技术研究 BD 中 CC 神经解剖学变化的最新研究结果。
在 2022 年 3 月之前，在 PubMed、Scopus 和 Web of Science 数据集上进行了文献检索。符合纳入标准的研究有 10 项。
从回顾的 DTI 束追踪研究中，BD 患者的 CC 体、膝部和压部的各向异性分数（FA）与对照组相比显著降低。这一发现与纤维密度的减少和纤维束长度的改变有关。最后，还报道了小内囊和整个 CC 的径向和平均弥散度的增加。
样本量小，在方法学（扩散梯度）和临床（终生合并症、BD 状态、药物治疗）特征方面存在异质性。
总之，这些发现表明 BD 患者的 CC 存在结构改变，这可能反过来解释了这种精神疾病中经常观察到的认知障碍，特别是在执行处理、运动控制和视觉记忆方面。最后，结构改变可能表明功能信息量的减少和 CC 连接的那些脑区的形态学影响。
