Quantitative tractography reveals changes in the corticospinal tract in drug-naïve children with attention-deficit/hyperactivity disorder

Abstract

Background: The specific role of the corticospinal tract with respect to inattention and impulsive symptoms in children with attentiondeficit/hyperactivity disorder (ADHD) has been explored in the past. However, to our knowledge, no study has identified the exact regions of the corticospinal tract that are affected in ADHD. We aimed to determine comprehensive alterations in the white matter microstructure of the corticospinal tract and underlying neuropsychological substrates in ADHD. Methods: We recruited 38 drug-naïve children with ADHD and 34 typically developing controls. We employed a tract-based quantitative approach to measure diffusion parameters along the trajectory of the corticospinal tract, and we further correlated alterations with attention and response inhibition measures. Results: Compared with controls, children with ADHD demonstrated significantly lower fractional anisotropy and higher radial diffusivity at the level of cerebral peduncle, and higher fractional anisotropy at the level of the posterior limb of the internal capsule in the right corticospinal tract only. As well, increased fractional anisotropy in the posterior limb of the internal capsule was negatively correlated with continuous performance test attention quotients and positively correlated with reaction time on the Stroop Colour-Word Test; increased radial diffusivity in the right peduncle region was positively correlated with omissions in the Stroop test. Limitations: The sample size was relatively small. Moreover, we did not consider the different subtypes of ADHD and lacked sufficient power to analyze subgroup differences. Higher-order diffusion modelling is needed in future white matter studies. Conclusion: We demonstrated specific changes in the right corticospinal tract in children with ADHD. Correlations with measures of attention and response inhibition underscored the functional importance of corticospinal tract disturbance in ADHD.

Exploring white matter functional networks in children with attention-deficit/hyperactivity disorder

“…Previous studies have provided microstructural and functional evidence of abnormalities within circuits or networks in patients with ADHD. Diffusion MRI studies found altered fractional anisotropy in several distributed WM tracts, including frontostriatal fibre tracts ( Wu et al , 2014 ), the corticospinal tract ( Bu et al , 2019 ) and other WM bundles ( Hong et al , 2014 ), which indicates the existence of disrupted WM microstructure. Regarding functional aspects, reduced functional connectivity within regions of the DMN ( Posner et al , 2014 ; Gao et al , 2019 ), the DAN ( Zhu et al , 2008 ; Cortese et al , 2012 ; McCarthy et al , 2013 ), the VAN and the FPN ( Hart et al , 2013 ; Yerys et al , 2019 ) has been reported.…”

Multivariate associations between behavioural dimensions and white matter across children and adolescents with and without attention‐deficit/hyperactivity disorder

“…We also found another two microstructural variations in different section of cortico‐cerebellar circuits, which include lower FA, higher MD, RD and AD in internal capsule and corticofugal fibres in brainstem, and higher FA, lower MD, RD and AD in cerebellum. Previously, our work showed distinct microstructural alterations in the internal capsule and cerebral peduncle (Bu, Liang, et al., 2020 ; Bu, Yang, et al., 2020 ), and the cortico‐cerebellar circuit is implicated in inhibitory control of ADHD (Hart, Radua, Nakao, Mataix‐Cols, & Rubia, 2013 ; Sathyanesan et al., 2019 ). Together, our findings suggest that distinct disruptions in different section of cortico‐cerebellar circuits may underlie both executive dysfunction and externalizing behaviour.…”

“…Together, these results indicated multiple white matter patterns involved in different brain circuits may give rise to ADHD heterogenous presentations. With more recent evidence about the presence of fMRI signal in white matter (Ji, Liao, Chen, Zhang, & Wang, 2017 ; Li et al., 2019 ) and its significant relevance to psychiatric disorders, including ADHD (Bu, Liang, et al., 2020 ; Bu, Yang, et al., 2020 ; Li et al., 2020 , 2021 ), it is worth investigating functional properties of white matter in the future besides the microstructural property, which can be complementary to help understand the role of white matter in ADHD psychopathology.…”

Maturational Indices of the Cognitive Control Network Are Associated with Inhibitory Control in Early Childhood

“…Specifically, research in ADHD has revealed that dysfunctional coupling in the SLF is associated with saccadic abnormalities (Fried et al, 2014;Matsuo et al, 2015) and increased response time variability (Wolfers et al, 2015). The corticospinal tract, in contrast, has functionally been linked to the control of voluntary movements (Kolb & Whishaw, 2009), and alterations of the corticospinal tract have been associated with the hyperactivity syndrome in ADHD (Bu et al, 2020). Our results, therefore, suggest that brain structures subserving different functional components of cognitive control, including attention regulation and motor control, mature in early childhood that might enable young children to first master behavioral IC tasks in cognitive contexts.…”