THE PLEASURE CENTRES
For a species to survive, its members must carry out such vital functions as eating, reproducing, and responding to aggression. Evolution has therefore developed certain areas in our brain whose role is to provide a pleasurable sensation as a “reward” for carrying out these vital functions.
These areas are interconnected with one another to form what is known as the “reward circuit”.
The ventral tegmental area (VTA), a group of neurons at the very centre of the brain, plays an especially important role in this circuit. The VTA receives information from several other regions that tell it how well various fundamental needs, and more specifically human needs, are being satisfied.
The VTA then forwards this information to another structure further forward in the brain: the nucleus accumbens. To send this information to the nucleus accumbens, the VTA uses a particular chemical messenger: dopamine. The increase in the level of dopamine in the nucleus accumbens, and in other brain regions, reinforces the behaviours by which we satisfy our fundamental needs.