González-Madruga Karen, Staginnus Marlene, Fairchild Graeme
Department of Psychology, Middlesex University, London, UK.
Department of Psychology, University of Bath, Bath, UK.
Curr Top Behav Neurosci. 2022;57:445-481. doi: 10.1007/7854_2022_345.
Attention-Deficit/Hyperactivity Disorder (ADHD) is increasingly viewed as a disorder of brain connectivity. We review connectivity-based theories of ADHD including the default mode network (DMN) interference and multiple network hypotheses. We outline the main approaches used to study brain connectivity in ADHD: diffusion tensor imaging and resting-state functional connectivity. We discuss the basic principles underlying these methods and the main analytical approaches used and consider what the findings have told us about connectivity alterations in ADHD. The most replicable finding in the diffusion tensor imaging literature on ADHD is lower fractional anisotropy in the corpus callosum, a key commissural tract which connects the brain's hemispheres. Meta-analyses of resting-state functional connectivity studies have failed to identify spatial convergence across studies, with the exception of meta-analyses focused on specific networks which have reported within-network connectivity alterations in the DMN and between the DMN and the fronto-parietal control and salience networks. Overall, methodological heterogeneity between studies and differences in sample characteristics are major barriers to progress in this area. In addition, females, adults and medication-naïve/unmedicated individuals are under-represented in connectivity studies, comorbidity needs to be assessed more systematically, and longitudinal research is needed to investigate whether ADHD is characterized by maturational delays in connectivity.
注意缺陷多动障碍（ADHD）越来越被视为一种大脑连接障碍。我们回顾了基于连接性的ADHD理论，包括默认模式网络（DMN）干扰和多重网络假说。我们概述了用于研究ADHD大脑连接性的主要方法：扩散张量成像和静息态功能连接性。我们讨论了这些方法的基本原理以及所使用的主要分析方法，并思考这些发现告诉了我们关于ADHD连接性改变的哪些信息。在关于ADHD的扩散张量成像文献中，最可重复的发现是胼胝体（连接大脑半球的关键连合纤维束）的分数各向异性较低。静息态功能连接性研究的荟萃分析未能确定不同研究之间的空间一致性，不过专注于特定网络的荟萃分析除外，这些分析报告了DMN内以及DMN与额顶叶控制网络和突显网络之间的网络内连接性改变。总体而言，研究之间的方法学异质性以及样本特征的差异是该领域取得进展的主要障碍。此外，在连接性研究中，女性、成年人以及未用药/未接受药物治疗的个体代表性不足，需要更系统地评估共病情况，并且需要进行纵向研究来调查ADHD是否具有连接性发育延迟的特征。
