Tamm Leanne, Dudley Jonathan A, Karalunas Sarah L, Simon John O, Maloney Thomas C, Atluri Gowtham, Epstein Jeffery N
Department of Pediatrics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.
University of Cincinnati College of Medicine, Medical Sciences Building, P.O. Box 670761, Cincinnati, OH, 45267, USA.
Neuroimage Rep. 2025 Jun;5(2). doi: 10.1016/j.ynirp.2025.100263. Epub 2025 Apr 14.
Patients with ADHD evidence elevated reaction time variability (RTV) due to periodic long reaction times (RTs). Even though reaction time variability (RTV) reflects intraindividual differences in RT across time, prior research exploring the neural basis of RTV in ADHD has primarily examined associations between neural activation and summary RTV outcomes (e.g., standard deviation of reaction time, tau). Here, we explore group differences in the neural basis of RTV by examining association between trial-level RTs and fMRI BOLD activation obtained during a Stop Signal Task in a large ( = 5719) sample of 9- to 10-year-old children participating in the Adolescent Brain Cognitive Development (ABCD) study. Children with ADHD demonstrated greater RTV than those without ADHD. ADHD-related group differences were not observed between fMRI BOLD activation and summary RTV outcomes. At the trial level, longer RTs were associated with increased BOLD activation in salience/ventral attention and executive control networks and decreased BOLD activation in the default mode network, consistent with time-on-task effects (i.e., stimulus processing time) in which long RTs require maintaining task-positive activation and DMN suppression for more time than short RTs. Moreover, children with ADHD showed weaker associations between long RTs and BOLD activation in these regions than children without ADHD supporting models that point to dysregulated competition between the DMN and executive network as mechanism of cognitive impairment in ADHD.
患有注意力缺陷多动障碍（ADHD）的患者由于周期性的长反应时间（RT）而表现出反应时间变异性（RTV）升高。尽管反应时间变异性（RTV）反映了个体在不同时间的反应时间内差异，但先前探索ADHD中RTV神经基础的研究主要考察了神经激活与RTV总体结果（例如，反应时间标准差、tau）之间的关联。在此，我们通过检查在一项停止信号任务中获得的试验水平反应时间（RT）与功能磁共振成像（fMRI）血氧水平依赖（BOLD）激活之间的关联，来探索9至10岁参与青少年大脑认知发展（ABCD）研究的大样本（n = 5719）儿童中RTV神经基础的组间差异。患有ADHD的儿童比没有ADHD的儿童表现出更大的RTV。在fMRI BOLD激活与RTV总体结果之间未观察到与ADHD相关的组间差异。在试验水平上，较长的RT与突显/腹侧注意网络和执行控制网络中BOLD激活增加以及默认模式网络中BOLD激活减少相关，这与任务执行时间效应（即刺激处理时间）一致，其中长RT比短RT需要更长时间维持任务积极激活和抑制默认模式网络。此外，与没有ADHD的儿童相比，患有ADHD的儿童在这些区域的长RT与BOLD激活之间的关联较弱，这支持了将默认模式网络与执行网络之间竞争失调作为ADHD认知障碍机制的模型。
