Amongst its many functions in the brain, dopamine plays an important role in pleasure systems, including those governing motivation and reward. Naturally enjoyable experiences such as food and sex cause dopamine release. Some drugs, such as cocaine and amphetamine, also lead to dopamine release, either directly or indirectly. A small study from researchers at Vanderbilt University has now shown that the people with ‘novelty-seeking’ personality traits process dopamine differently from more risk-averse individuals. The study, in 34 healthy men and women, found that thrill-seeking was inversely linked to the density of dopamine auto-receptors, receptors on dopamine-producing cells that switch off production when dopamine levels rise. Fewer auto-receptors mean higher levels of the neurotransmitter which may in turn trigger a bigger reward from new and risky experiences. Having fewer auto-receptors may also make giving up pleasurable experiences more difficult, and New Year’s resolutions that bit harder to keep.
The study is published in the Journal of Neuroscience.