Professor Trevor Robbins explains that the dopamine system is a group of cells originating in the midbrain whose function may be to prepare the brain to think, move, and anticipate rewards.
The dopamine system is basically a group of nerve cells, most of which originate in the midbrain. They send their axons to the forebrain, to different parts of the forebrain, where they plug into particular functions. Now, I would say, to simplify things, that there are three main branches of this forebrain dopamine system.
There’s a branch that goes all the way to the frontal cortex, where it modulates cognitive function and enhances the efficiency of certain forms of thinking and working memory.
There is a very famous branch which goes to a structure called the striatum, which is implicated in Parkinson’s disease. Here dopamine is involved in facilitating movements. So in Parkinson’s disease, when you lose dopamine, your movements become rigid and rather reduced in number and amplitude.
The third important branch of the dopamine system is that it goes to structures in the limbic system of the brain, which is the emotional center of the brain, including the nucleus accumbens, which has often been called the reward center. Many drugs of abuse exert their effects indirectly or sometimes directly through this reward dopamine system.
In general, I think that the dopamine system may work as one thing. It may work to prepare you for thinking, for movement, and for reward. And that’s its main function. It functions in anticipation of behavioral and cognitive output.
The basal ganglia, a group of interconnected brain areas located deep in the cerebral cortex, have proved to be at work in learning, the formation of good and bad habits, and some psychiatric and addictive disorders.