The Role of Stress Neuromodulators in Decision Making Under Risk (Part II)

Study Overview
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Brief Summary
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The aim of the proposed project is to combine precise pharmacological manipulation of the noradrenergic system with behavioral modeling of memory processes, and fMRI methods to study the effect of a pharmacologically induced blockade of the noradrenergic system on memory processes. Behaviorally, the investigators will focus on the effect of the noradrenergic blockade on working memory performance, and recognition memory.

Detailed Description
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Affective states like acute stress can influence cognition, i.e., memory processes. Physiologically, acute stress elicits an array of autonomic and endocrine responses, including a fast release of norepinephrine from the locus coeruleus noradrenergic (LC NA) system. Compelling evidence shows that in healthy humans, stimulation of the noradrenergic system increases memory performance whereas noradrenergic blockade reduces memory performance. Functional magnetic resonance imaging (fMRI) studies have shown that manipulations of the noradrenergic system affects responsiveness and connectivity within networks that are important for autonomic-neuroendocrine control and temporal and spatial attention orientation. So far, no study investigated the neural underpinnings of memory processes after a pharmacologically induced noradrenergic blockade. The aim of the proposed project is to combine precise pharmacological manipulation of the noradrenergic system with behavioral modeling of distinct memory processes, and fMRI methods to study the effect of a pharmacologically induced blockade of the noradrenergic system on two distinct memory processes. Behaviorally, the investigators will focus on the effect of the noradrenergic blockade on working memory performance, and recognition memory. Participants are randomly assigned to one of two groups: (A) clonidine, or (B) placebo.

Official Title
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The Role of Stress Neuromodulators in Decision Making Under Risk

Conditions
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Stress

Intervention / Treatment
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* Drug: Clonidin
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: right handed, high-school diploma Exclusion Criteria: former & present DSM-5 axis I disorders, medication,

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 |
| --- | --- |
| Experimental: Clonidin<br>pill 0,15 mg clonidin | Drug: Clonidin<br>* 0,15mg Clonidin orally versus placebo pill<br>|
| Placebo Comparator: Placebo<br>placebo pill | Drug: Placebo<br>* placebo pill<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Working Memory (n-back task) | Behavioral outcome of emotional two-back task = number of correct answers / button presses | 11 minutes | 
| Recognition Memory (word list learning) | Behavioral outcome of word recognition task = number of correctly recognized words | 25 minutes | 
| Blood-oxygen-level-dependent (BOLD) response | fMRI data | 46 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| blood pressure | Treatment check | 2.5 hours | 
| Heart rate | Treatment check | 2.5 hours | 
| salivary cortisol | Treatment check | 2.5 hours |