Brain activation deficit in increased-load working memory tasks among adults with ADHD using fMRI

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• Working memory (WM) deficits are common in adults with attention-deficit hyperactivity disorder (ADHD).
• Understanding the neural basis of WM impairments in ADHD is crucial for developing targeted interventions.

Purpose of the Study:

• To investigate brain activation patterns during low-level and increased-load working memory tasks in adults with ADHD compared to controls.
• To identify specific brain regions and networks associated with WM deficits in ADHD.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan 20 adults with ADHD and 20 controls.
• Participants completed phonological and visual-spatial 2-back and 3-back tasks to assess working memory capacity and brain activation.

Main Results:

• Both groups activated the fronto-parietal network for WM, with greater intensity in the ADHD group for phonological tasks.
• Adults with ADHD showed decreased activation in the left precuneus, insula, and SMA as WM load increased, unlike controls.
• The ADHD group exhibited greater deactivation in the left fronto-parietal network with increased WM load.

Conclusions:

• Adults with ADHD may exert more effort on less demanding working memory tasks.
• Impaired brain activation within the left fronto-parietal network occurs when working memory demands exceed the capacity of adults with ADHD.