Oxytocin and Interpersonal Motor Resonance

Study Overview
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Brief Summary
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Among different social cues from the environment, the eyes constitute a very salient source for initiating social interaction or communication. Interestingly, previous work from our (Prinsen et al., 2016) and other labs demonstrated that direct eye contact between two individuals can readily evoke an increased propensity to 'mirror' other peoples' actions. Particularly, using transcranial magnetic stimulation (TMS), the investigators showed that mirror-motor mapping at the level of the primary motor cortex (M1), also known as interpersonal motor resonance (IMR), is significantly increased upon the observation of actions accompanied by direct eye contact, compared to the observation of actions accompanied by averted eye gaze. With the present study, the investigators aim to investigate the role of eye contact on IMR further, and in particular, explore whether administration of the 'prosocial' neuropeptide oxytocin (OT) can influence eye-contact induced IMR. In general, OT is known to play an important role in promoting prosocial behavior and the perception of socially-relevant stimuli, such as eye gaze. To date however, the link between OT and IMR is less clear.

Detailed Description
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In the present study, the investigators want to explore how a single-dose of intranasally administered OT can modulate interpersonal motor resonance (IMR) and/or the enhanced effects of eye contact on IMR. To investigate the effects of exogenous OT administrations, the investigators adopted a double-blind, within-subjects (cross-over), randomized, placebo-controlled trial. The investigators will recruit approximately 30 neurotypical young adults males between 18 - 35 years old. Since a cross-over design is included, subjects will participate in two sessions, separated by one week. Participants will be randomly assigned to receive a single dose of OT (24 international units) or placebo nasal spray at the first and second session. In each session, the non-invasive brain stimulation technique 'transcranial magnetic stimulation' (TMS) will be used at the level of the primary motor cortex to obtain an end-state measure of unconscious 'mirror-motor mapping' or IMR. During TMS, participants will observe video stimuli of a model performing simple, intransitive hand movements combined with either direct or averted gaze. Additionally, behavioral measures will be included: social attachment and social responsiveness will be assessed via self-report questionnaires and eye tracking technology will be included to monitor participant's spontaneous gaze behavior. The main statistical analysis of the neurophysiological data will have the within-subjects factor of administered nasal spray (OT or PL), observed gaze direction (direct or averted gaze) and observed movement (opening hand movement or no movement). Furthermore, the link between the neurophysiological (TMS) and behavioral measures (questionnaire data and gaze behavior) will be investigated.

Official Title
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Oxytocin-based Pharmacotherapy: Investigating the Effect on Interpersonal Motor Resonance Upon Direct Eye Gaze

Conditions
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Social Behavior

Intervention / Treatment
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* Drug: Oxytocin
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male Young adults (between 18 - 35 y/o) Right-handed Exclusion Criteria: Left-handed Any neuro(psycho)logical / psychiatric illness. Motor dysfunctions of the hands / arms. Any contradiction to TMS research as assessed with the TMS screening list: no pacemaker, implanted defibrillator, ear implant / a cochlear implant, insulin or implanted pump, a neurostimulator or ventriculoperitoneal shunt, any metallic object in the eyes (metallic fragments)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Oxytocin (OT) spray<br>Syntocinon nasal spray (product code RVG 03716) will be used to intranasally administer one single dose (24 IU) of OT (3 puffs of 4 IU per nostril). | Drug: Oxytocin<br>* A single dose (24IU) of nasal spray (3 puffs of 4IU per nostril) will be administered before the assessment of the neurophysiological measures.<br>* Other names: Syntocinon (product code RVG 03716);|
| Placebo Comparator: Placebo (PL) spray<br>Physiological water (a solution of sodium chloride (NaCl) in water) will be used to intranasally administer one single dose (24 IU) of PL (3 puffs of 4 IU per nostril). | Other: Placebo<br>* A single dose (24IU) of nasal spray (3 puffs of 4IU per nostril) will be administered before the assessment of the neurophysiological measures.<br>* Other names: Physiological water (sodium chloride (NaCl) solution);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of interpersonal motor resonance (IMR) | TMS will be applied to assess IMR during different observational conditions after a single dose of nasal spray | 30 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| State Adult Attachment Measure (SAAM) (sub)scores | Informant-based self-report questionnaire assessing social attachment. | 10 minutes | 
| Social Responsiveness Scale (SRS) (sub)scores | Informant-based self-report questionnaire assessing social responsiveness. | 20 minutes | 
| Spontaneous gaze behavior | During movement observation, participants' viewing behavior will be monitored by means of eye tracking technology. | 30 minutes | 
| Participants' mood | Informant-based self-report score on Profiles of Mood States questionnaire to control for differences in mood between sessions. | 10 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Oxytocin, Gaze processing, Interpersonal motor resonance