Review of functional neuroimaging research in attention-deficit/hyperactivity disorder

What are the potential contributions of functional neuroimaging to diagnosing, understanding the pathophysiology, and treating attention-deficit/hyperactivity disorder (ADHD)? This article briefly reviews the clinical aspects of ADHD, the neuroimaging techniques, the major caveats to functional neuroimaging, the cognitive models of ADHD, and the results of the most important studies. These studies include the examination of basal cerebral activity (at rest or during the performance of a simple vigilance test to maintain alertness) and the effects of stimulants on basal cerebral activity; neurotransmitter function (dopaminergic function); and cognitive activation using tasks that target cognitive dysfunction in ADHD. Findings consistently show fronto-striatal hypofunction in studies of basal activity and cognitive activation; discrete cerebral abnormalities in adolescents that become more generalized in adults; and dopaminergic abnormalities that differ between adults and adolescents. Finally, future directions of functional neuroimaging research in ADHD are discussed.