Several lines of research based on structural and/or functional imaging techniques, stimulant drugs, psychological interventions have identified alterations in the dopaminergic and adrenergic pathways of individuals with ADHD. In particular, areas of the prefrontal cortex appear to be the most affected. Dopamine and norepinephrine are neurotransmitters which play an important role in brain function. The uptake transporters for dopamine and norepinephrine are overly active and clear these neurotransmitters from the synapse a lot faster than in normal individuals. This is thought to increase processing latency and salience, and diminished working memory.