January 01, 2009
Fewer Dopamine Receptors Means More Novelty Seeking

Thrill seeking and increased risk of drug abuse might stem from having fewer of a type of dopamine receptor.

NASHVILLE, Tenn.--For risk-takers and impulsive people, New Year's resolutions often include being more careful, spending more frugally and cutting back on dangerous behavior, such as drug use. But new research from Vanderbilt finds that these individuals--labeled as novelty seekers by psychologists--face an uphill battle in keeping their New Year's resolutions due to the way their brains process dopamine. The research reveals that novelty seekers have less of a particular type of dopamine receptor, which may lead them to seek out novel and exciting experiences--such as spending lavishly, taking risks and partying like there's no tomorrow.

The research was published Dec. 31, 2008, in the Journal of Neuroscience.

The neurotransmitter dopamine is produced by a select group of cells in the brain. These dopamine-producing cells have receptors called autoreceptors that help limit dopamine release when these cells are stimulated.

"We've found that the density of these dopamine autoreceptors is inversely related to an individual's interest in and desire for novel experiences," David Zald, associate professor of psychology and lead author of the study, said. "The fewer available dopamine autoreceptors an individual has, the less they are able to regulate how much dopamine is released when these cells are engaged. Because of this, novelty and other potentially rewarding experiences that normally induce dopamine release will produce greater dopamine release in these individuals."

The researchers used positron emission topography (PET) brain scans to help them reach this conclusion.

The researchers used positron emission topography to view the levels of dopamine receptors in 34 healthy humans who had taken a questionnaire that measured the novelty-seeking personality trait. The questionnaire measured things such as an individual's preference for and response to novelty, decision-making speed, a person's readiness to freely spend money, and the extent to which a person is spontaneous and unconstrained by rules and regulations. The higher the score, the more likely the person was to be a novelty seeker.

The researchers found that those that scored higher on the novelty-seeking scale had decreased dopamine autoreceptor availability compared to the subjects that scored lower.

If it becomes possible to use a drug to increase the number of dopamine autoreceptors will some thrill-seekers or perhaps some drug abusers opt to change their brain in such a fundamental way in order to gain greater ability to control and restrict their own actions? I can imagine compulsive spenders opting for such a treatment. But skiers, skydivers, and other thrill seekers might decide they'd rather continue to pursue extreme sports.

Share |      Randall Parker, 2009 January 01 12:48 AM  Brain Addiction


Comments
Jake said at January 1, 2009 3:35 PM:

It would be interesting to count the number of dopamine autoreceptors of habitual criminals.

A survey was done asking criminals in prison why they committed crimes. Over half said they enjoyed the risk and thrill of crime. They had no other reason.

Xenophon Hendrix said at January 2, 2009 8:35 AM:

As can be seen with anti-depressants, people are willing to adjust their brain chemistries to make their lives more tolerable, and the technology is still crude. As long as the risks of long-term damage are small, I'm sure people will be happy to twiddle with their brains as the technologies become available.

Have you read about the Big Five (or Five Factor) model of personality? (If you haven't, search engines turn up some good introductions.) It appears that personality differences tend to fall into five broad groupings when they are subjected to factor analysis. One of the things I'm interested in is how neurotransmitters and related brain structures correspond to the Big Five personality traits.

One day, we might be able to adjust our brains to make ourselves be the kind of people we fantasize about being. Another thing I speculate about are the tradeoffs. For example, it seems likely that the traits needed to be adventurous will also unavoidably make it so that one is also easily bored.

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