Effects of Oxytocin and Lorazepam on Fear-related Intra-amygdalar Activity

Study Overview
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Brief Summary
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High-potency benzodiazepines have strong anxiolytic effects accompanied by significant adverse effects including impaired cognitive function, drowsiness, dizziness and impaired motoric abilities. Importantly, the long-term use of benzodiazepines may produce dependence and withdrawal. Therefore, there is considerable scientific and public interest in identifying new anxiolytic agents. The hypothalamic peptide oxytocin (OXT) has anxiolytic effects both in healthy participants and patients with anxiety disorders by decreasing fear-associated amygdala activity. However, so far no human study has directly compared the underlying anxiolytic mechanisms of OXT and established anxiolytic agents on amygdala activity. Importantly, the amygdala is not a homogenous structure but rather consists of several subdivisions with structural and functional differences. Therefore, the rationale of the present project is to determine the effects of intranasal OXT and the high-potency benzodiazepine lorazepam on fear-associated responses in intra-amygdalar subregions.

Official Title
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Common and Dissociable Effects of Oxytocin and Lorazepam on the Neurocircuitry of Fear - an Ultra-high Field Imaging Study

Conditions
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Oxytocin, Lorazepam, Anti-Anxiety Agents, Physiological Effects of Drugs

Intervention / Treatment
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* Drug: Oxytocin
* Drug: Lorazepam 1 mg
* Drug: Placebo nasalspray
* Drug: Placebo Oral Tablet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy male volunteers right-handed Exclusion Criteria: Current or past psychiatric illness Current or past physical illness Psychoactive medication Sedative medication MRI contraindication (e.g. metal in body, claustrophobia)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 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 |
| --- | --- |
| Active Comparator: Oxytocin or PLC<br>Single dose of intranasal oxytocin (24 international units) or PLC. | Drug: Oxytocin<br>* Intranasal administration, 24 international units (IU) oxytocin<br>* Other names: syntocinon;Drug: Placebo nasalspray<br>* The placebo nasalspray contain identical ingredients except for the active agent itself.<br>|
| Active Comparator: Lorazepam or PLC<br>Single dose of lorazepam (1mg) or PLC | Drug: Lorazepam 1 mg<br>* Oral administration of 1mg lorazepam<br>* Other names: Tavor;Drug: Placebo Oral Tablet<br>* The placebo pill contain identical ingredients except for the active agent itself.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neural responses to emotional faces in the amygdala subregions | Functional magnetic resonance imaging (fMRI) will be performed to measure blood-oxygen-level dependent signal in response to emotional face stimuli. The investigators specifically plan to investigate amygdala subregion responses to emotional faces. | Neural activations with be measured with 7 Tesla fMRI in an emotional face matching task that lasts 20 mins | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Amygdala, anxiety, benzodiazepines, fear, fMRI, lorazepam, oxytocin, 7 Tesla