How do stimulants change brain signaling in ADHD?

Stimulant medications increase the availability of dopamine and norepinephrine in key brain networks involved in attention, motivation, and self regulation. In ADHD, these neurotransmitters are regulated less efficiently, especially in the prefrontal cortex. Stimulants help strengthen signal transmission so information stays online longer and distractions are filtered more effectively. This improves initiation, working memory, and emotional regulation. Importantly, stimulants do not create focus out of nowhere. They make it easier for the brain to access focus when conditions are present. The effect is regulatory, not sedating or energizing in a typical sense.