BACKGROUND Previous research demonstrated atypical attention in children with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Regarding visual orienting, findings suggest a differential impairment: Atypical orienting to relatively unexpected targets in ASD, and atypical processing of alerting cues in ADHD. The locus coeruleus-norepinephrine (LC-NE) system plays an important role in exploiting alerting cues to increase attention and task performance. The present study's aim was to examine differential subcortical processes underlying visual orienting in ASD and ADHD with pupil dilation (PD) as index of LC activity. METHODS Pupil dilation (PD) progression metrics during visual orienting were calculated for task-evoked PD locked to cue, stimulus onset, and behavioral response. Group differences in PD and reaction time (RT) were compared between children with ASD without ADHD (ASD-) (N = 18), ADHD without ASD (ADHD-) (N = 28), both disorders (ASD + ADHD) (N = 14), and typically developing children (TD) (N = 31) using linear mixed models (LMM). To further explore the modulatory role of the LC-NE system group differences in the effect of task-evoked PD metrics on RT were examined exploratively. RESULTS ASD (+ADHD) showed slower orienting responses to relatively unexpected spatial target stimuli as compared to TD, which was accompanied by higher PD amplitudes relative to ADHD- and TD. In ADHD-, shorter cue-evoked PD latencies relative to ASD-, ASD + ADHD, and TD were found. Group differences in the effect of cue- and stimulus-evoked PD amplitudes on RT were found in ASD- relative to TD. CONCLUSIONS Study findings provide new evidence for a specific role of the LC-NE system in impaired reflexive orienting responses in ASD, and atypical visual processing of alerting cues in ADHD.

中文翻译：

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视觉空间定向期间的瞳孔扩张可区分自闭症谱系障碍和注意力缺陷/多动障碍。

背景 先前的研究表明，注意力缺陷/多动障碍 (ADHD) 和自闭症谱系障碍 (ASD) 儿童存在非典型注意力。关于视觉定向，研究结果表明存在差异性障碍：ASD 中对相对意外目标的非典型定向，以及 ADHD 中警报提示的非典型处理。蓝斑-去甲肾上腺素 (LC-NE) 系统在利用警报线索来提高注意力和任务绩效方面发挥着重要作用。本研究的目的是通过瞳孔扩张 (PD) 作为 LC 活动的指标来检查 ASD 和 ADHD 视觉定向的不同皮质下过程。方法 计算视觉定向期间的瞳孔扩张 (PD) 进展指标，用于锁定线索、刺激开始和行为反应的任务诱发 PD。比较无 ADHD 的 ASD 儿童 (ASD-) (N = 18)、无 ASD 的 ADHD (ADHD-) (N = 28)、两种疾病 (ASD + ADHD) (N) 的 PD 和反应时间 (RT) 组差异= 14)，并且通常使用线性混合模型 (LMM) 发展儿童 (TD) (N = 31)。为了进一步探索 LC-NE 系统组差异在任务诱发的 PD 指标对 RT 的影响中的调节作用，进行了探索性检查。结果 ASD (+ADHD) 与 TD 相比，对相对意外的空间目标刺激的定向反应较慢，伴随着相对于 ADHD- 和 TD 更高的 PD 幅度。在 ADHD- 中，发现了相对于 ASD-、ASD + ADHD 和 TD 更短的线索诱发 PD 潜伏期。相对于 TD，在 ASD 中发现了线索和刺激诱发的 PD 幅度对 RT 的影响的组差异。