Reward Mechanism Diminishes With Age
As people age, their brains respond less strongly to rewards, according to a study appearing on The Proceedings of the National Academy of Sciences' Web site, the New York Times reports. The main difference lies in the brain's response to dopamine.
The shifts in brain response might be reflected in attitude changes that accompany aging, said Dr. Karen Faith Berman of the National Institutes of Health, an author of the study.
"It may explain anecdotal evidence that people are mellower," she said, "that they may not get the same highs from certain experiences, but they may not get the same lows, either."
As two groups of volunteers, one in their 60s and the other in their 20s, played a computer game similar to a slot machine, the researchers performed brain scans on them.
Differences between the groups emerged when volunteers anticipated winning money in the game and when they actually did so, the researchers found. It wasn't just a matter of how much dopamine was produced, but also which parts of the brain responded to it and how much, the study said.
When a reward was anticipated, the researchers said, three parts of a reward center in the younger people's brains lighted up, but only one part in the older people's brains.