Brain-behavior relationships in task-based fMRI assessments of executive functions in children and adolescents with and without ADHD: a systematic review and ALE meta-analysis

Background
Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder affecting about 5% of children and adolescents worldwide. ADHD symptoms often reflect impairments in executive functions (EFs). Functional magnetic resonance imaging (fMRI), particularly task-based fMRI (tb-fMRI), has been crucial in studying the neural mechanisms behind ADHD and its EF deficits. However, few studies have examined differences in brain activation and behavioral outcomes between children with and without ADHD using tb-fMRI, or the correlation between brain activation and behavior.

Methods
This meta-analysis aimed to summarize evidence using activation likelihood estimation (ALE) analysis to identify differences in EFs and brain activation during tb-fMRI between children with and without ADHD. We retrieved published studies from PsychINFO, CINAHL Ultimate, Embase, MEDLINE, PubMed and Web of Science from inception through April 2024.

Results
Following systematic review guidelines, 32 studies using tb-fMRI to compare children with and without ADHD during EF tasks were included in the ALE analysis. Children with ADHD showed significant differences in inhibitory control and working memory compared to controls. They exhibited reduced activation during EF tasks in areas such as the bilateral inferior frontal gyrus, supramarginal gyrus, inferior parietal gyrus, angular gyrus, caudate, occipital gyrus, and cerebellum. Correlation analyses revealed positive associations between brain activation and inhibitory control in the inferior frontal gyrus and anterior cingulate cortex in the ADHD group, suggesting a link between increased neural activity and better EF performance.

Conclusion
The results of this study enhance our understanding of ADHDs pathophysiology and suggest potential pathways for developing interventions and therapies.