Control Group, Spray+ Group
Conditions
Keywords
social placebo effect, fMRI, neural account
Brief 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.
Interventions
BEHAVIORALspray+ manipulation
Participants in spray+ group received placebo manipulation and were told they sprayed was oxytocin (in fact, it was saline);
BEHAVIORALcontrol manipulation
Participants in control group were told they sprayed saline (in fact, it was saline).
Sponsors
Beijing Normal University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* All participants had normal or corrected-to-normal vision, and mental healthy.
Exclusion criteria
* Participants who reported no history of neurological, endocrine or psychiatric disorders, who majored in psychology in college or recently participated in any other drug study were not recruited.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The brain functional connectivity | 8 mins, 240 TR in scanner | For functional connectivity estimation, we adopted DLPFC, mPFC and reward related brain regions as the seeds to do whole-brain connectivity analysis. And the conducted two-sample T test to examine whether there would be some differences between spray+ and control groups. |
| Social brain network properties in resting-state | 8 mins, 240 TR in scanner | For the network properties, we chose the social brain network as our target and interested network, then estimated the global efficiency within this network.And the conducted two-sample T test to examine whether there would be some differences between spray+ and control groups. |
| The brain response pattern for the key concepts about oxytocin | 5.33mins, 160TR in scanner | We estimated the beta response trial by trial for each single concept and then investigated the neural representation of all concepts by using representational similarity analysis (RSA). |
Countries
China
Outcome results
None listed