Neuroscientists at the University of California, Berkeley have spotted the exact locations in the brain where calculations are made, can also lead to addictive and compulsive behavior.
They have found how neural activity in the brain's orbitofrontal and anterior cingulate cortex regulates our choices.
These astonishing new findings could pave the way for more targeted treatments for everything from drug and alcohol abuse to obsessive-compulsive disorders.
"The better we understand our decision-making brain circuitry, the better we can target treatment, whether it's pharmaceutical, behavioural or deep brain stimulation," said Jonathan Wallis, associate professor of psychology and neuroscience at UC Berkeley and the principal investigator of the study.
To test their hypothesis that these areas of the brain were the key players in impaired decision-making, the UC Berkeley researchers measured the neural activity of macaque monkeys as they played games in which they identified the pictures most likely to deliver juice through a spout into their mouths.
The animals quickly learned which pictures would most frequently deliver the greatest amount of juice, enabling researchers to see what calculations they were making, and in which part of the brain.
The results showed that the orbitofrontal cortex regulates neural activity, depending on the value or "stakes" of a decision. This part of the brain enables you to switch easily between making important decisions.
However, in the case of addicts and people with damage to the orbitofrontal cortex, the neural activity does not change based on the gravity of the decision, presenting trouble when these individuals try to get their brains in gear to make sound choices, the findings suggested.
As for the anterior cingulate cortex, the study found that when this part of the brain functions normally, we learn quickly whether a decision we made matched our expectations.
But in people with a malfunctioning anterior cingulate cortex, these signals are missing, and so they continue to make poor choices, Wallis said.
"This is the first study to pin down the calculations made by these two specific parts of the brain that underlie healthy decision-making," he stated.
Wallis said the findings offer hope that, through understanding the mechanism of addiction, treatment can be targeted at these risk-weighing, decision-making centres of the brain.
The study will be published in the Oct. 30 online issue of the journal Nature Neuroscience.