Relationship Between Serotonin and Brain Response to Social Dominance and Emotion Perception.

Study Overview
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Brief Summary
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Previous studies have already revealed the involvement of the serotoninergic system in the social behavior process. For example, more serotonin (5HT) was found in dominant male adult monkeys. Little is known about the serotoninergic implication in human's social behavior. The project aims to clarify the role of the serotoninergic system in social behavior in relation to the process of social hierarchical information. In order to determine how serotoninergic system is involved, the investigator will use a new technic TEP-fMRI. This technic allows us to measure the brain activity and the serotoninergic transporter occupancy (using the [C11]-DASB) at the same time. The current study aims to investigate whether serotonin transporter (5-HTT) activity correlates with the neural response (BOLD) during the detection of social dominance in facial expressions or other measures of social information processing. Blood sample, SLC6A4 (allele coding for the 5HT transporter) genotyping and neuropsychological questionnaires will give at the investigator more information and allow to investigate whether performance on social information processing is modulated by personality trait and genotype.

Official Title
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Relationship Between Serotonin and Brain Response to Social Dominance Perception and Emotion: a Combined [11C]DASB-PET/fMRI Study in Humans

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Device: PET-fMRI scan


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: French speaking Normal vision Age from 18 to 45 Without psychiatric antecedent Without any neurologic antecedent Not taking psychotropic or anxiolytic drugs Having health insurance coverage Exclusion Criteria: The subject does not wish to be notified of any anomalies detected during MRI Subjects suffering from claustrophobia Subjects carrying magnetic metal objects that cannot be removed as cochlear implant, surgical clips, piercings, pacemakers, mechanical valves Subjects participating in a clinical trial or being in a period of exclusion from a previous clinical trial Person under guardianship or curatorship or deprived of liberty or in emergencies Taking unauthorized treatment in the month before the completion of the review Person whose physical or mental condition does not allow him to pass the test study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dominance<br>Healthy subjects | Device: PET-fMRI scan<br>* fMRI scan include MR sequences: BOLD and fMRI. The PET acquisition will be carried out in dynamic for 90 consecutive minutes following intravenous administration of 4 MBq / kg dose of [11C]DASB bolus.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| level of Blood-Oxygen-Level Dependent (BOLD) signal | The BOLD signal will be measured using a MRI scanner, and simultaneously we will record the level of serotonin transporter with [11C]DASB marker of the serotonin transmission, using a PET signal. We will use the Scatchard method in order to determine the level of [11C]DASB bonded to the transporter. Our reference region will be the cerebellum. | at day 0 | 
| level of serotonin transporter | The BOLD signal will be measured using a MRI scanner, and simultaneously we will record the level of serotonin transporter with [11C]DASB marker of the serotonin transmission, using a PET signal. We will use the Scatchard method in order to determine the level of [11C]DASB bonded to the transporter. Our reference region will be the cerebellum. | at day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Behavioral assessment | During the entire scanner, subjects will be ask to perform a behavioral task. Their responses will be analyzed. | at day 0 | 
| Testosterone Blood level | The testosterone will be measured on a blood sample. | after the scan session at day 0 | 
| Cortisol Blood level | The cortisol will be measured on a blood sample (prelevated at same time than testosterone). | after the scan session at day 0 | 
| SLC6A4 genotyping | The genotyping of this gene (SLC6A4) will be realized on a sample of saliva. | at day 0 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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PET-fMRI, dominance, 5HT transporter