In the study, reported in the May 25 issue of the journal Science, rats trained to understand that they can have one sugar pellet now or four later soon catch on to the idea that waiting can bring sweet rewards. A naturally-occurring substance called dopamine may help explain this phenomenon.
Dopamine is one of the chemicals that allow communication between nerves in the brain.
It is also known to be involved in the sensation of reward we experience from something we enjoy. WebMD it's been known for a long time that natural rewards, like food and sex, as well as artificial ones, like nicotine and cocaine, act on dopamine to activate the nucleus accumbens. The conclusion that the nucleus accumbens is at the center of our reward system is bolstered by a second study published in the May issue of the journal Neuron . The researchers found that as the prospect of winning more money increased, so did activity in the parts of the brain previously seen to respond to other types of rewards, such as drugs. The level of activity in the nucleus accumbens and two other nearby regions grew as the potential jackpot increased in the expectancy phase, and similar changes were seen during the outcome phase.