WASHINGTON  —  A person's optimism in the future seems to be controlled by a small front part of the mid-brain, according to a study that used brain imaging.

That area deep behind the eyes activates when people think good thoughts about what might happen in the future.

The more optimistic a person is, the brighter the area showed up in brain scans, the scientists reported in a small study published online Thursday in the journal Nature.

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That same part of the brain, called the rostral anterior cingulate cortex (rACC), seems to malfunction in people suffering depression, said the study co-authors, Elizabeth Phelps of New York University and Tali Sharot of University College London.

Researchers gave 15 people functional magnetic resonance imaging scans while they thought about future possibilities.

When the participants thought about good events, both the rACC and amygdala, which is involved in emotional responses including fear, were activated. But the correlation with optimism was biggest with the cingulate cortex.

The same study also found that people tended to think that happier events were closer in time and more vivid than the bad ones, even if they had no reason to believe it, Phelps said.

Psychologists have long known people have an "optimism bias," but the new study offers new details.

When researchers asked the subjects to think about 80 different future events that could be good, bad or neutral, they had a hard time getting people to think negatively, or even neutrally, about the future.

For example, when people were asked to ponder a future haircut, they imagined getting the best haircut of their lives, instead of just an ordinary trim, Phelps said.

The study makes sense and pulls together new and different parts of research on optimism and the brain, said Dan Schacter, a professor of psychology at Harvard University who wasn't part of the research.

Having our brains wired to optimism is generally a good thing because "if you were pessimistic about the future you would not be motivated to take a lot of action," Phelps said.