Pediatric ADHD symptom burden relates to distinct neural activity across executive function domains

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent childhood disorder marked by inattention and/or hyperactivity symptoms. ADHD may also relate to impaired executive function (EF), but is often studied in a single EF task per sample. The current study addresses the question of unique vs. overlapping relations in brain activity across multiple EF tasks and ADHD symptom burden. Three in-scanner tasks drawn from distinct EF domains (cognitive flexibility, working memory, and inhibition) were collected from children with and without an ADHD diagnosis (N = 63). Whole-brain activity and 11 regions of interest were correlated with parent reports of inattention and hyperactivity symptoms. Across the three EF domains, brain activity related to ADHD symptom burden, but the direction and location of these associations differed across tasks. Overall, activity in sensory and default mode network regions related to ADHD, and these relations did not consistently overlap across EF domains. We observed both distinct and overlapping patterns for inattention and hyperactivity symptoms. By studying multiple EF tasks in the same sample, we identified a heterogenous neural profile related to attention symptom burden in children. Our results inform ADHD characterization and treatment and explain some of the variable brain results related to EF and ADHD reported in the literature

The consistency of control engagement in developmental populations

Control regions of the brain flexibly respond to changing task demands and support cognitive abilities that are important for learning and academic success. Deficits in task control brain function have been implicated in developmental learning disorders of reading and attention, which often present with overlapping behavioral characteristics. This dissertation presents three studies that use a multi-task approach to explore associations between academic or behavioral skills and control brain function in children with and without learning difficulties. Study 1 investigated task control activation across lexical and non-lexical tasks in a sample of 3rd-5th grade struggling readers. We found altered control engagement in struggling readers during a reading task, but not during a non-lexical task, suggesting that altered engagement of control in struggling readers is specific to the reading process rather than a reflection of a global control deficit. Study 2 investigated consistencies across different tasks in control brain activation when children made mistakes relative to when they responded correctly. We found that the majority of adult-derived brain regions important during errors also showed consistent engagement in children across three tasks, except in bilateral frontal areas, which may be regions that distinguish mature from immature error processing. Study 3 assessed brain activation during and after errors on two tasks in children with and without attention-deficit/hyperactivity disorder (ADHD). We found that children engaged primarily cingulo-opercular and parietal task control regions during error trials, but both cingulo-opercular and fronto-parietal control regions during the trials after an error. During error processing, we found activation differences between children with and without ADHD in default, sensorimotor, and visual systems, and regions within these systems showed task-specific differences. Examining the consistency of control activation across tasks provides insight into domain-general or task-specific neural mechanisms that have the potential to be markers of difficulty, or targets for intervention, in children with learning or attention disorders.Psycholog

Consistent Performance Differences between Children and Adults Despite Manipulation of Cue-Target Variables

Two behavioral experiments assessed the plasticity and short-term improvement of task switching in 215 children and adults. Specifically, we studied manipulations of cued attention to different features of a target stimulus as a way to assess the development of cognitive flexibility. Each experiment had multiple levels of difficulty via manipulation of number of cued features (2–4) and number of response options (2 or 4). Working memory demand was manipulated across the two experiments. Impact of memory demand and task level manipulations on task accuracy and response times were measured. There were three overall goals: First, these task manipulations (number of cued features, response choices, and working memory load) were tested to assess the stability of group differences in performance between children ages 6–16 years and adults 18–27 years, with the goal of reducing age group differences. Second, age-related transitions to adult-level performance were examined within subgroups of the child sample. Third, short-term improvement from the beginning to the end of the study session was measured to probe whether children can improve with task experience. Attempts to use task manipulations to reduce age differences in cued task switching performance were unsuccessful: children performed consistently worse and were more susceptible to task manipulations than adults. However, across both studies, adult-like performance was observed around mid-adolescence, by ages 13-16 years. Certain task manipulations, especially increasing number of response options when working memory demand was low, produced differences from adults even in the oldest children. Interestingly, there was similar performance improvement with practice for both child and adult groups. The higher memory demand version of the task (Experiment 2) prompted greater short-term improvement in accuracy and response times than the lower memory demand version (Experiment 1). These results reveal stable differences in cued switching performance over development, but also relative flexibility within a given individual over time

Pediatric ADHD symptom burden relates to distinct neural activity across executive function domains

Pediatric ADHD symptom burden relates to distinct neural activity across executive function domains Tehila Nugiel, Mary Abbe Roe, Laura E. Engelhardt, Mackenzie E. Mitchell, Annie Zheng, Jessica A. Church. Attention-deficit/hyperactivity disorder (ADHD) is a prevalent childhood disorder marked by inattention and/or hyperactivity symptoms. ADHD may also relate to impaired executive function (EF), but is often studied in a single EF task per sample. The current study addresses the question of unique vs. overlapping relations in brain activity across multiple EF tasks and ADHD symptom burden. Three in-scanner tasks drawn from distinct EF domains (cognitive flexibility, working memory, and inhibition) were collected from children with and without an ADHD diagnosis (N=63). Whole-brain activity and 11 regions of interest were correlated with parent reports of inattention and hyperactivity symptoms. Across the three EF domains, brain activity related to ADHD symptom burden, but the direction and location of these associations differed across tasks. Overall, activity in sensory and default mode network regions related to ADHD, and these relations did not consistently overlap across EF domains. We observed both distinct and overlapping patterns for inattention and hyperactivity symptoms. By studying multiple EF tasks in the same sample, we identified a heterogenous neural profile related to attention symptom burden in children. Our results inform ADHD characterization and treatment and explain some of the variable brain results related to EF and ADHD reported in the literature. Contact: Tehila Nugiel [email protected]

Children’s head motion during fMRI tasks is heritable and stable over time

Head motion during fMRI scans negatively impacts data quality, and as post-acquisition techniques for addressing motion become increasingly stringent, data retention decreases. Studies conducted with adult participants suggest that movement acts as a relatively stable, heritable phenotype that serves as a marker for other genetically influenced phenotypes. Whether these patterns extend downward to childhood has critical implications for the interpretation and generalizability of fMRI data acquired from children. We examined factors affecting scanner motion in two samples: a population-based twin sample of 73 participants (ages 7–12 years) and a case-control sample of 32 non-struggling and 78 struggling readers (ages 8–11 years), 30 of whom were scanned multiple times. Age, but not ADHD symptoms, was significantly related to scanner movement. Movement also varied as a function of task type, run length, and session length. Twin pair concordance for head motion was high for monozygotic twins and moderate for dizygotic twins. Cross-session test-retest reliability was high. Together, these findings suggest that children’s head motion is a genetically influenced trait that has the potential to systematically affect individual differences in BOLD changes within and across groups. We discuss recommendations for future work and best practices for pediatric neuroimaging. Keywords: Head motion, fMRI, Twin study, Repeated measures, Individual difference