Through studying people who describe themselves as happy and engaged in life versus those who report feelings of depression and anxiety, neuroscientists have been able to pinpoint brain regions that exhibit corresponding activity.
one study found that increased activity in the left side of the prefrontal cortex coincides with negative emotional states .
In the case of happiness, the neurotransmitter dopamine relays information from the limbic system (which regulates emotional experiences) to the prefrontal cortex, and individuals with more sensitive dopamine receptors tend to be more cheerful.
Accordingly, some people may be more genetically predisposed to happiness than others.