The role of oxytocin in social decision-making - An investigation into the effects of oxytocin on human brain and behavior

Animal studies showed that oxytocin, a hormone and a neurotransmitter, plays an
important role in the formation of social, affiliative behavior. Recent
evidence suggests that oxytocin is involved in prosocial behavior of humans as
well. Intranasal administration of oxytocin in humans has been reported to
enhance trust, empathy and social engagement. However, knowledge on how
oxytocin affects the brain mechanisms underlying social behavior is scarce. The
main objective of our research is therefore to develop insights into how
oxytocin modulates the neural correlates of interactive social decision-making.

Primary objective:
To identify the neural mechanisms via which oxytocin modulates social
decision-making.

Secondary objectives:
- To provide an extension of observed behavioral effects of oxytocin on
decision-making, specifically to examine decisions made in a social context
- To identify whether oxytocin is involved in social risk-taking or in
risk-taking in general
- To evaluate whether the effect of oxytocin on social decision-making is
moderated by personality variables
- To contribute to a better understanding of the neuroendocrine systems
underlying social mental disorders

Participants will be tested in a randomized, double-blind, placebo controlled,
between-group design. Participants will receive either oxytocin or a similar
placebo dose and perform computerized tasks in an MRI scanner. Brain images
will be used to identify the effects of oxytocin on the neural correlates of
social decision-making. After scanning, participants will complete several
self-report questionnaires.

One group of participants will self-administer 24 IU of Syntocinon - the
synthetic analogue of oxytocin - by an intranasal spray. Another group will
self-administer a similar dose of placebo.

The low dose of oxytocin can be administered safely to humans without any
relevant risk of serious adverse events.
On both the day prior to the test session and on the day of the test session
itself participants will adhere to some simple restrictions with respect to
medication, alcohol and drug intake. During the morning of the test session
participants will refrain from smoking and consuming stimulant-containing
drinks. The risk associated with participation can be considered negligible and
the burden can be considered minimal. No adverse events are expected and side
effects of the treatment are very unlikely.