The brain image at the top left is a PET image from a normal control subject. The striatum is brightly lit in red and yellow, indicating the presence of many dopamine transporters, which contrasts with the brain of a methamphetamine abuser (bottom left). What does this mean functionally? The graphs on the right show the relationship between performance on a motor (upper right) and a memory task (lower right) and methamphetamine-driven decreases in dopamine transporters. The magnitude of the decline in the dopamine transporter binding is positively correlated with the extent of motor and memory impairment; thus the greater the decline, the greater the impairment in memory and motor reaction time.
As a result of scientific research, we know that addiction is a disease that affects both brain and behavior.