Ferdowsi Cognitive Science and Technology Center & Medical Imaging Lab, Department of Electrical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Vakil-Abad Blv., Bahonar St., Mashhad, 9177948974, Iran.
INSERM U1105, Université de Picardie, CURS, Avenue Laennec, 80054, Amiens, France.
Cereb Cortex. 2024 Aug 1;34(8). doi: 10.1093/cercor/bhae335.
Hyperactivity in children with attention-deficit/hyperactivity disorder (ADHD) leads to restlessness and impulse-control impairments. Nevertheless, the relation between ADHD symptoms and brain regions interactions remains unclear. We focused on dynamic causal modeling to study the effective connectivity in a fully connected network comprised of four regions of the default mode network (DMN) (linked to response control behaviors) and four other regions with previously-reported structural alterations due to ADHD. Then, via the parametric empirical Bayes analysis, the most significant connections, with the highest correlation to the covariates ADHD/control, age, and sex were extracted. Our results demonstrated a positive correlation between ADHD and effective connectivity between the right cerebellum and three DMN nodes (intrinsically inhibitory connections). Therefore, an increase in the effective connectivity leads to more inhibition imposition from the right cerebellum to DMN that reduces this network activation. The lower DMN activity makes leaving the resting-state easier, which may be involved in the restlessness symptom. Furthermore, our results indicated a negative correlation between age and these connections. We showed that the difference between the average of effective connectivities of ADHD and control groups in the age-range of 7-11 years disappeared after 14 years-old. Therefore, aging tends to alleviate ADHD-specific symptoms.
儿童多动症（ADHD）患者的多动会导致不安和冲动控制障碍。然而，ADHD 症状与大脑区域之间的相互作用关系仍不清楚。我们专注于动态因果建模，以研究由默认模式网络（DMN）的四个区域（与反应控制行为相关）和四个由于 ADHD 而先前报道有结构改变的其他区域组成的全连接网络中的有效连接。然后，通过参数经验贝叶斯分析，提取与 ADHD/对照组、年龄和性别等协变量相关性最高的最显著连接。我们的研究结果表明，ADHD 与右小脑和三个 DMN 节点（内在抑制连接）之间的有效连接之间存在正相关。因此，有效连接的增加会导致右小脑对 DMN 的抑制作用增强，从而降低该网络的激活程度。DMN 的活性降低会使人们更容易离开静息状态，这可能与不安症状有关。此外，我们的研究结果还表明，年龄与这些连接之间存在负相关。我们发现，ADHD 组和对照组之间的有效连接平均值在 7-11 岁年龄范围内的差异在 14 岁以后消失。因此，年龄的增长有助于缓解 ADHD 特有的症状。
