Differential patterns of striatal activation in young children with and without ADHD

Background Cognitive control, defined as the ability to suppress inappropriate thoughts and actions, is compromised in attention-deficit/hyperactivity disorder (ADHD). This study examines the neural basis of this deficit. Methods We used a paradigm that incorporates a parametric manipulation within a go/nogo task, so that the number of go trials preceding a nogo trial is varied to tax the neural systems underlying cognitive control with increasing levels of interference. Results Using this paradigm in combination with event-related functional magnetic resonance imaging (fMRI), we show that children without ADHD have increased susceptibility to interference with increasing numbers of go trials preceding a nogo trial, but children with ADHD have difficulty even with a single go trial preceding a nogo trial. In addition, children with ADHD do not activate frontostriatal regions in the same manner as normally developing children, but rather rely on a more diffuse network of regions, including more posterior and dorsolateral prefrontal regions. Conclusions Normal immature cognition may be characterized as being susceptible to interference and supported by the maturation of frontostriatal circuitry. ADHD children show a slightly different cognitive profile at 6 to 10 years of age that is paralleled by a relative lack of or delay in the maturation of ventral frontostriatal circuitry.