Saad Jacqueline Fifi, Griffiths Kristi R, Korgaonkar Mayuresh S
Brain Dynamics Centre, Westmead Institute for Medical Research, Westmead Hospital, Sydney, NSW, Australia.
The Discipline of Psychiatry, Sydney Medical School, The University of Sydney, Camperdown, NSW, Australia.
Front Integr Neurosci. 2020 Jun 24;14:31. doi: 10.3389/fnint.2020.00031. eCollection 2020.
Insights to underlying neural mechanisms in attention deficit hyperactivity disorder (ADHD) have emerged from neuroimaging research; however, the neural mechanisms that distinguish ADHD subtypes remain inconclusive. We reviewed 19 studies integrating magnetic resonance imaging [MRI; structural (sMRI), diffusion, functional MRI (fMRI)] findings into a framework exploring pathophysiological mechanisms underlying the combined (ADHD-C) and predominantly inattentive (ADHD-I) ADHD subtypes. Despite equivocal structural MRI results, findings from fMRI and DTI imaging modalities consistently implicate disrupted connectivity in regions and tracts involving frontal striatal thalamic in ADHD-C and frontoparietal neural networks in ADHD-I. Alterations of the default mode, cerebellum, and motor networks in ADHD-C and cingulo-frontoparietal attention and visual networks in ADHD-I highlight network organization differences between subtypes. Growing evidence from neuroimaging studies highlight neurobiological differences between ADHD clinical subtypes, particularly from a network perspective. Understanding brain network organization and connectivity may help us to better conceptualize the ADHD types and their symptom variability.
神经影像学研究已揭示了注意力缺陷多动障碍（ADHD）潜在的神经机制；然而，区分ADHD亚型的神经机制仍无定论。我们回顾了19项研究，这些研究将磁共振成像[MRI；结构（sMRI）、扩散张量成像、功能MRI（fMRI）]结果整合到一个框架中，以探索合并型（ADHD-C）和主要为注意力不集中型（ADHD-I）ADHD亚型潜在的病理生理机制。尽管结构MRI结果不明确，但fMRI和DTI成像方式的研究结果一致表明，ADHD-C中涉及额叶-纹状体-丘脑区域和神经束的连接性中断，而ADHD-I中额顶神经网络的连接性中断。ADHD-C中默认模式、小脑和运动网络的改变，以及ADHD-I中扣带回-额顶注意力和视觉网络的改变，突出了各亚型之间的网络组织差异。神经影像学研究越来越多的证据凸显了ADHD临床亚型之间的神经生物学差异，尤其是从网络角度来看。了解脑网络组织和连接性可能有助于我们更好地理解ADHD的类型及其症状变异性。
