Intrinsic brain abnormalities in attention deficit hyperactivity disorder: a resting-state functional MR imaging...

Area of Science:

• Neuroscience
• Developmental Psychology
• Radiology

Background:

• Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder.
• Executive dysfunction is a core symptom in ADHD, affecting planning and cognitive control.
• Resting-state functional magnetic resonance imaging (fMRI) is a valuable tool for investigating intrinsic brain activity.

Purpose of the Study:

• To investigate regional and network-level neural function alterations in children and adolescents with ADHD using resting-state fMRI.
• To determine the relationship between intrinsic neural activity changes and executive dysfunction in ADHD.

Main Methods:

• A prospective study involving 33 boys with ADHD (aged 6-16) and 32 healthy controls (aged 8-16).
• Resting-state fMRI was used to assess Amplitude of Low-Frequency Fluctuation (ALFF) for regional function and functional connectivity (FC) for network integration.
• Executive function was assessed using the Wisconsin Card Sorting Test and Stroop Color-Word Test.

Main Results:

• ADHD participants demonstrated significantly impaired executive function compared to controls.
• Lower ALFF was observed in the left orbitofrontal cortex and left ventral superior frontal gyrus in ADHD.
• Higher ALFF was found in the globus pallidus and right dorsal superior frontal gyrus in ADHD.
• Reduced long-range FC in frontoparietal and frontocerebellar networks, and increased FC in the frontostriatal circuit were noted in ADHD.
• Altered FC in the frontostriatal circuit correlated with the degree of executive dysfunction in ADHD.

Conclusions:

• ADHD is characterized by focal brain hyper- and hypofunction.
• Altered connectivity within large-scale resting-state networks is a key feature of ADHD.
• These connectivity alterations are directly associated with executive dysfunction, suggesting a connectivity-based pathophysiology in ADHD.