One way to understand ADD neurologically is as a lack of inhibition, a chronic underactivity of the prefrontal cortex. The cerebral cortex in the frontal lobe is not able to perform its job of prioritizing, selection and inhibition. The brain, flooded with multiple bits of sensory data, thoughts, feelings and impulses, cannot focus, and the mind or body cannot be still. In short, the policeman is asleep. If we want the traffic to move, we need to rouse him. Similarly, the cortex is functioning at a semidormant level, as indicated by the EEG finding of slowed activity. Hence the efficacy of stimulant medications: they arouse the inhibitory function. They wake up the cop, alert the underdeveloped and underactive circuitry of the prefrontal cortex.