Neuroimaging of Inhibitory Control Areas in Children With Attention Deficit Hyperactivity Disorder Who Were Treatment Naive or in Long-Term Treatment

Objective: Difficulty with response inhibition is a cardinal symptom of attention deficit hyperactivity disorder (ADHD), combined type. Prefrontal and cingulate brain regions are known to be involved in inhibitory control. Event-related functional magnetic resonance imaging (fMRI) might establish if these regions differ in their activity in ADHD children relative to healthy comparison subjects. Method: Fifteen healthy comparison subjects and 17 children with ADHD, combined type, completed fMRI studies while performing the Stop Signal Task. Eight ADHD subjects were treatment naive; the remainder had a history of long-term treatment with stimulants, but they were medication free at the time of the fMRI. No subject had a learning disorder or a comorbid psychiatric condition (other than oppositional defiant disorder in the ADHD subjects). Results: Both the ADHD and comparison subjects activated the right dorsolateral prefrontal cortex on “stop” trials relative to “go” trials; this increase was greater in ADHD...