Oxytocin Modulation of Startle Reactivity to Social Stimuli and Moral Decision Making

Study Overview
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Brief Summary
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The purpose of this study is to determine whether oxytocin affects the modulation of startle reactivity by aversive social stimuli and to investigate the oxytocin effect on moral judgements. Furthermore the investigators explore the effects of oxytocin receptor (OXTR) polymorphisms on behavioral responses to social stimuli.

Detailed Description
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The neuropeptide oxytocin (OXT) can enhance the impact of positive social cues but may reduce that of negative ones, although it is unclear whether the latter causes blunted emotional responses. After OXT or placebo application participants are exposed to acoustic startle probes presented alone and during viewing of 60 color pictures mostly selected from the 'International Affective Picture System'. The paradigm featured 20 negative (mostly threatening), 20 neutral, and 20 positive pictures, presented for 5 s each. In the other part of the experiment, after intranasal OXT or placebo application participants respond to 60 moral dilemmas.

Official Title
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Double-blind, Placebo-controlled, Randomized Study: Oxytocin Modulation of Startle Reactivity to Social Stimuli and Moral Decision Making

Conditions
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Healthy Male Volunteers

Intervention / Treatment
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* Drug: Oxytocin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy male volunteers Exclusion Criteria: Current or past psychiatric disease Current or past physical illness Psychoactive medication Tobacco smokers

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Oxytocin<br>24 IU Oxytocin, intranasal application 45 min prior to the experiment | Drug: Oxytocin<br>* Oxytocin: 24 IU; 3 puffs per nostril, each with 4 IU OXT<br>* Other names: Oxytocin: Syntocinon-Spray, Novartis;|
| Placebo Comparator: Placebo<br>intranasal application, sodium chloride solution, 3 puffs per nostril | Drug: Oxytocin<br>* Oxytocin: 24 IU; 3 puffs per nostril, each with 4 IU OXT<br>* Other names: Oxytocin: Syntocinon-Spray, Novartis;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| baseline startle magnitude and affective modulation of the startle magnitude after oxytocin and placebo administration | The experimental tasks started 45 min after intranasal OXT/PLC administration. The STARTLE-paradigm features 20 negative (mostly threatening), 20 neutral, and 20 positive pictures, presented for 5 s each. The startle stimulus consists of a single 50-ms burst of white noise (100 dB) with nearly instantaneous rise and was delivered binaurally via headphones during 60% of the pictures (i.e. 12 from each category) at 2 - 4 s after picture onset. We examined the baseline startle magnitude as well as the affective modulation of the startle magnitude. | 24 Months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| moral decision making after oxytocin and placebo administration | The experimental tasks started 45 min after OXT/PLC administration. The moral dilemmas performed in the present study were identical to those published previously by Greene et al.(2001). | 24 months | 
| oxytocin receptor (OXTR) polymorphism and correlation with social behavior | OXTR genotyping, social behavior testing | 24 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Oxytocin, Startle, moral dilemma, oxytocin receptor gene