NCT03891459

Neural Account of Social Placebo Effect

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 68 (actual)
• Sponsor: Beijing Normal University · Academic / Other
• Sex: Male
• Age: 18 Years – 35 Years
• Healthy volunteers: Accepted

Summary

The current study aimed to reveal the neural mechanism of social placebo belief formation and belief representation, and also investigated how the brain pattern predict the social behavior performance under placebo manipulation.

Detailed description

Participants were randomly assigned to spray+ group (sprayed with saline but told as "oxytocin") and control group (sprayed with saline but told as "saline"). After 10 min, participants were invited to the resting-state, text viewing task in fMRI scanner. In resting state session, participants with their eyes open and were instructed to attend to a black fixation cross centrally presented on a grey projection screen for 8 min (240TR). The Text viewing task employed a mixed block and even-related fMRI design. Participants were asked to judge whether they could understand the stimuli or not by a button press (1=understand; 2=not understand). Three kinds of stimuli were presented in separate block including "oxytocin-function", "oxytocin-knowledge", "robot" related stimuli, each category contained 20 sentences. In each block, the sentence (within one category) was presented pseudo-randomized from 5s to 9s (with mean duration of 7s), then followed by a jittered time interval (interval time = sentence duration - response time; if participants made response within 5s, the sentence would not disappear until its duration reached 5s). There were two sessions with six blocks per session, and there were 5 sentences (trials) per block. The order of blocks and sentences were designed to present in pseudo-random order and were applied to all participants.

Conditions

• Spray+ Group
• Control Group

Interventions

Type	Name	Description
BEHAVIORAL	spray+ manipulation	Participants in spray+ group received placebo manipulation and were told they sprayed was oxytocin (in fact, it was saline);
BEHAVIORAL	control manipulation	Participants in control group were told they sprayed saline (in fact, it was saline).

Timeline

• Start date: 2018-06-27
• Primary completion: 2018-11-02
• Completion: 2018-11-05
• First posted: 2019-03-27
• Last updated: 2019-03-27

Locations

1 site across 1 country: China