Vasopressin and Pain Perception in the Brain

Study Summary

The feeling of pain is not just a sensory experience, but is also influenced by emotions, beliefs and expectations, making pain a highly subjective experience. This is evident in clinical practice, where the behavior of the physician and the treatment context can strongly influence the pain experience of patients. Research has shown that patients' expectation that a treatment will reduce pain influences individual perception of pain, even if the treatment has no active ingredient. The expectancy-induced analgesia emerges due to a modulation of the individual pain experience of patients by an engagement of endogenous inhibitory systems in the central nervous system. The development of expectancy-induced analgesia can be generated in several ways. The investigators have previously demonstrated that social information and observational learning (e.g. the patient observes analgesia in another person receiving a treatment) can lead to expectancy-induced analgesia and pain reduction. However, the neural mechanisms (mechanisms in the brain) of how these expectancies are acquired and the neural mechanisms of analgesia induced by observational learning are unknown. The investigators recently established a procedure to investigate neural mechanisms of observational learning in placebo analgesia. Here the investigators propose to investigate the influence of vasopressin, a neurotransmitter that is important for social interaction, on observational learning. The investigators will use functional magnetic resonance imaging (fMRI), a non-invasive method, to investigate neural activity in humans. Participants will either receive vasopressin or saline with a nasal spray. During fMRI scanning, participants will then undergo an observational learning phase, where the study participants will learn the experience of analgesia in another person through a video, and a testing phase, where participants will perceive painful stimulations with the same cues as the observational phase. Th

Primary Outcome

Blood oxygenation level dependent (BOLD) responses will allow the identification of relative activation/deactivation in the brain as a result of events (e.g. painful stimulations) that will be given during the experiment. Changes in the Percentage of BOLD signal are calculated as the BOLD signal in the right supplementary motor area during the 20-second heat pain divided by the whole-brain average BOLD signal during that 20-second heat pain.

Conditions Studied

Interventions

• OTHER Saline
• DRUG Arginine vasopressin
• BEHAVIORAL Observational learning
• OTHER fMRI data aquisition

Study Locations (1)