These scans looking down on the brain are measuring dopamine activity in the nucleus accumbens and reflect levels of interest, drive and motivation.
A recent research finding is that people who are born with below average receptors (D2) in this area are more likely to develop behavioral and/or substance addictions.
Conversely, people born with above average numbers of these receptors are relatively protected from developing addictions.
The function of this area of the brain is to learn what is pleasurable and then fire to activate our systems of pursuit. Mother nature wants us to be motivated to eat and have sex. These are natural activators of the nucleus accumbens.
In addictions this part of the brain is “hijacked” by some behavior, like gambling or alcohol/drugs.
Tolerance frequently develops to addictive substances and results in a depletion of dopamine. Low dopamine causes craving for substances that have powerful effects on the dopamine system – like speed, cocaine, or alcohol.
