Fronto-parietal white matter microstructure associated with working memory performance in children with ADHD

Area of Science:

• Neuroscience
• Developmental Psychology
• Radiology

Background:

• Attention Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder impacting executive functions, particularly working memory.
• The superior longitudinal fasciculus (SLF) is crucial for working memory development in neurotypical children.
• Reduced white matter organization in the SLF is hypothesized to underlie working memory deficits in ADHD.

Purpose of the Study:

• To investigate the association between SLF white matter organization and working memory in children with ADHD.
• To compare SLF volume and apparent fibre density (AFD) between children with ADHD and controls.

Main Methods:

• Diffusion magnetic resonance imaging (dMRI) and constrained spherical deconvolution-based tractography were used to analyze the SLF.
• Working memory was assessed using a computerized spatial n-back task in 64 children with ADHD and 58 controls (aged 9-11).
• Tract volume and AFD of the SLF branches were quantified bilaterally.

Main Results:

• Children with ADHD demonstrated poorer working memory performance, characterized by increased reaction time and variability (RT and RT-V).
• Lower volume and AFD of the left SLF-II were observed in children with ADHD compared to controls.
• Left SLF-II volume significantly mediated the relationship between ADHD and working memory performance.

Conclusions:

• The findings highlight the role of frontoparietal white matter integrity, specifically the left SLF-II, in working memory impairments associated with ADHD.
• This research contributes to understanding the neurobiological underpinnings of executive function deficits in ADHD.