Gencheva Teodora M, Valkov Bozhidar V, Kandilarova Sevdalina S, Maes Michael H J, Stoyanov Drozdstoy S
Faculty of Medicine, Medical University of Plovdiv, Plovdiv, Bulgaria.
Department of Psychiatry and Medical Psychology, and Research Institute, Medical University of Plovdiv, Plovdiv, Bulgaria.
Acta Psychiatr Scand. 2025 Mar;151(3):192-209. doi: 10.1111/acps.13742. Epub 2024 Aug 13.
The aim of this systematic review is to assess the functional magnetic resonance imaging (fMRI) studies of bipolar disorder (BD) patients that characterize differences in terms of structural, functional, and effective connectivity between the patients with BD, patients with other psychiatric disorders and healthy controls as possible biomarkers for diagnosing the disorder using neuroimaging.
Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), guidelines a systematic search for recent (since 2015) original studies on connectivity in bipolar disorder was conducted in PUBMED and SCOPUS.
A total of 60 studies were included in this systematic review: 20 of the structural connectivity, 33 of the functional connectivity, and only 7 of the studies focused on effective connectivity complied with the inclusion and exclusion criteria.
Despite the great heterogeneity in the findings, there are several trends that emerge. In structural connectivity studies, the main abnormalities in bipolar disorder patients were in the frontal gyrus, anterior, as well as posterior cingulate cortex and differences in emotion and reward-related networks. Cerebellum (vermis) to cerebrum functional connectivity was found to be the most common finding in BD. Moreover, prefrontal cortex and amygdala connectivity as part of the rich-club hubs were often reported to be disrupted. The most common findings based on effective connectivity were alterations in salience network, default mode network and executive control network. Although more studies with larger sample sizes are needed to ascertain altered brain connectivity as diagnostic biomarker, there is a perspective that the method could be used as a single marker of diagnosis in the future, and the process of adoption could be accelerated by using approaches such as semiunsupervised machine learning.
本系统评价的目的是评估双相情感障碍（BD）患者的功能磁共振成像（fMRI）研究，这些研究旨在确定BD患者、其他精神疾病患者和健康对照在结构、功能和有效连接方面的差异，以此作为使用神经影像学诊断该疾病的潜在生物标志物。
按照系统评价和Meta分析的首选报告项目（PRISMA）指南，在PUBMED和SCOPUS中对近期（自2015年以来）关于双相情感障碍连接性的原始研究进行了系统检索。
本系统评价共纳入60项研究：20项关于结构连接性，33项关于功能连接性，只有7项专注于有效连接性的研究符合纳入和排除标准。
尽管研究结果存在很大异质性，但仍出现了一些趋势。在结构连接性研究中，双相情感障碍患者的主要异常出现在额前回、前扣带回以及后扣带回皮质，以及情绪和奖赏相关网络的差异。小脑（蚓部）与大脑的功能连接被发现是BD中最常见的发现。此外，作为富俱乐部枢纽一部分的前额叶皮质和杏仁核连接性经常被报道受到破坏。基于有效连接性的最常见发现是突显网络、默认模式网络和执行控制网络的改变。尽管需要更多样本量更大的研究来确定大脑连接性改变作为诊断生物标志物，但有一种观点认为该方法未来可作为单一诊断标志物，并且通过使用半监督机器学习等方法可以加速其应用过程。
