Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

It’s a gamble: dopamine levels tied to uncertainty of rewards

10.05.2004


Researchers, using a new combination of techniques, have discovered that dopamine levels in our brains vary the most in situations where we are unsure if we are going to be rewarded, such as when we are gambling or playing the lottery.


David Zald
©Vanderbilt University



The research results, "Dopamine Transmission in the Human Striatum during Monetary Reward Tasks," were published online April 28 in the Journal of Neuroscience.

Dopamine has long been known to play an important role in how we experience rewards from a variety of natural sources, including food and sex, as well as from drugs such as cocaine and heroin, but pinning down the precise conditions that cause its release has been difficult.


"Using a combination of techniques, we were actually able to measure release of the dopamine neurotransmitter under natural conditions using monetary reward," said David Zald, assistant professor of psychology at Vanderbilt University.

Zald believes the primary significance of the study is the possibilities it raises for future research on measuring what causes us to experience reward from a variety of sources and what happens in our brains when we are disappointed in our quest for those rewards. The research lays a foundation for a better understanding of what happens in the brain during unpredictable reward situations such as gambling and offers promise for exploring the chemical foundation of problems such as gambling addiction.

"We’re moving to a point where we can measure what’s happening to people’s neurotransmitter systems in a way that we haven’t been able to do before," he said.

Zald and his colleagues used positron emission topography (PET scanners) to view brain activity in nine human research subjects who had been injected with a chemical that binds to dopamine receptors in the brain, but is less able to bind when the brain is releasing dopamine. A decrease in binding to the receptors is associated with an increase in dopamine release, while an increase in binding indicates reduced release of dopamine. This technique allows researchers to study the strength and location of dopamine release more precisely than has previously been possible.

The team studied the subjects under three different scenarios. Under the first scenario, the subject selected one of four cards and knew a monetary reward of $1 was possible but did not know when it would occur. During the second scenario, subjects knew they would receive a reward with every fourth card they selected. Under the third scenario, subjects chose cards but did not receive or expect any rewards.

Zald and his team found that over the course of the experiment, dopamine transmission increased more in one part of the brain in the unpredictable first scenario, while showing decreases in neighboring regions. In contrast, the receipt of a reward under the predictable second scenario did not result in either significant increases or decreases in dopamine transmission.

"It’s probably not just the receipt of money, but the conditions under which it occurs which makes a difference," Zald explained.

The increase and suppression were localized to specific, separate regions of the brain, illustrating that variable reward scenarios, like gambling, have a complex effect on the brain.

"The most interesting thing we found is that there were areas that showed increased dopamine release during the unpredictable condition, and there were also other areas showing decreased dopamine release," Zald said.

"So other than just dopamine as reward, there is a more complicated action occurring."

The data was collected in Montreal and analyzed in collaboration with Gabriel Dichter at Vanderbilt; Isabelle Boileau and Alain Dagher at McGill University, Montreal; Wael El-Dearedy at Liverpool John Moores University, United Kingdom; Roger Gunn at Glaxo SmithKline, Greenford, United Kingdom; and Francis McGlone, Unilever Research, Wirral, United Kingdom.

The research was supported by grants from Unilever Research and the National Science Foundation. Zald is a member of the Vanderbilt Kennedy Center for Research on Human Development.

Media contact: Melanie Catania, (615) 322-NEWS
Melanie.catania@vanderbilt.edu

Melanie Catania | Vanderbilt University
Further information:
http://sitemason.vanderbilt.edu/newspub/bjfTyg?id=11881

More articles from Studies and Analyses:

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

Bodyguards in the gut have a chemical weapon

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>