Brain's 'trust machinery' identified

May 21, 2008

The brain centers triggered by a betrayal of trust have been identified by researchers, who found they could suppress such triggering and maintain trust by administering the brain chemical oxytocin. The researchers said their findings not only offer basic insights into the neural machinery underlying trust; the results may also help in understanding the neural basis of social disorders such as phobias and autism.

Thomas Baumgartner and colleagues published their findings in the May 22, 2008, issue of the journal Neuron, published by Cell Press.

In their experiments, the researchers asked volunteer subjects to play two types of games--a trust game and a risk game. In the trust game, subjects were asked to contribute money, with the understanding that a human trustee would invest the money and decide whether to return the profits, or betray the subjects' trust and keep all the money. In the risk game, the subjects were told that a computer would randomly decide whether their money would be repaid or not.

The subjects also received doses of either the brain chemical oxytocin (OT) or a placebo via nasal spray. They chose OT because studies by other researchers had shown that OT specifically increases people's willingness to trust others.

During the games, the subjects' brains were scanned using functional magnetic resonance imaging. This common analytical technique involves using harmless magnetic fields and radio waves to map blood flow in brain regions, which reflects brain activity.

The researchers found that--in the trust game, but not the risk game--OT reduced activity in two brain regions: the amygdala, which processes fear, danger and possibly risk of social betrayal; and an area of the striatum, part of the circuitry that guides and adjusts future behavior based on reward feedback.

Baumgartner and colleagues concluded that their findings showed that oxytocin affected the subjects' responses specifically related to trust.

"If subjects face the nonsocial risks in the risk game, OT does not affect their behavioral responses to the feedback. Both subjects in the OT group and the placebo group do not change their willingness to take risks after the feedback. In contrast, if subjects face social risks, such as in the trust game, those who received placebo respond to the feedback with a decrease in trusting behavior while subjects with OT demonstrate no change in their trusting behavior although they were informed that their interaction partners did not honor their trust in roughly 50% of the cases."

The researchers also wrote that "our insights into the neural circuitry of trust adaptation, and oxytocin's role in trust adaptation, may also contribute to a deeper understanding of mental disorders such as social phobia or autism that are associated with social deficits. In particular, social phobia (which is the third most common mental health disorder) is characterized by persistent fear and avoidance of social interactions."

Rutgers University psychologist Mauricio Delgado, in a preview in the same issue of Neuron, wrote that the paper "represents an ambitious and informative development in the literature," He commented that the study "has significant implications for understanding mental disorders where deficits in social behavior are observed. Betrayal aversion, for example, could serve as a precursor to social phobia, a disorder characterized by aversion to social interactions, with the reported oxytocin finding providing a bridge for potential clinical applications."
-end-
The researchers include Thomas Baumgartner, University of Zurich, Zurich, Switzerland; Markus Heinrichs, University of Zurich, Zurich, Switzerland; Aline Vonlanthen, University of Zurich, Zurich, Switzerland; Urs Fischbacher, University of Zurich, Zurich, Switzerland; and Ernst Fehr, University of Zurich, Zurich, Switzerland, Collegium Helveticum, Zurich, Switzerland.

Cell Press

Related Mental Disorders Articles from Brightsurf:

Mental health disorders among university students confined during COVID-19
University students in France who experienced quarantine during COVID-19 were surveyed to assess how common were mental health issues and to identify factors associated with these disorders.

Care for veterans with substance use and mental health disorders needs improvement
While the availability of services for veterans has expanded in recent years, many post-9/11 veterans do not receive appropriate care for their co-occurring substance use and mental health problems, according to a new study.

Infant sleep problems can signal mental disorders in adolescents -- Study
Specific sleep problems among babies and very young children can be linked to mental disorders in adolescents, a new study has found.

Mental disorders in the family affects the treatment of people with bipolar disorder
Patients with bipolar disorder who have multiple family members with severe mental disorders, are more difficult to treat and require more medicine.

Researchers call for new approach to some mental disorders
Depression, anxiety and PTSD might not be disorders at all, according to a recent paper by Washington State University biological anthropologists.

Mapping health risks for people with mental disorders
Researchers now have the ability to map the risks of general medical conditions such as heart and lung diseases, diabetes and cancer for people with mental disorders.

Spinal cord injury increases risk for mental health disorders
A new study finds adults with traumatic spinal cord injury are at an increased risk of developing mental health disorders and secondary chronic diseases compared to adults without the condition.

Maternal hypertensive disorders may lead to mental health disorders in children
Hypertensive pregnancy disorders, especially preeclampsia -- may increase the risk of psychological development disorders and behavioral and emotional disorders in children.

Critically injured soldiers have high rates of mental health disorders
U.S. combat soldiers who suffered a moderate or severe traumatic brain injury (TBI) are more likely than soldiers with other serious injuries to experience a range of mental health disorders, according to a new retrospective study by University of Massachusetts Amherst health services researchers.

Brain imaging may improve diagnosis and treatment of mental health disorders
Brain imaging may one day be used to help diagnose mental health disorders--including depression and anxiety--with greater accuracy, according to a new study conducted in a large sample of youth at the University of Pennsylvania and led by Antonia Kaczkurkin, PhD and Theodore Satterthwaite, MD.

Read More: Mental Disorders News and Mental Disorders Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.