Oxytocin and Interpersonal Motor Resonance
Condition: Social Behavior
Study type: Interventional
Phase: Phase 4

Summary: 
      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: 
      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.
    

Intervention name(s): Oxytocin; Placebo
Intervention type(s): Drug; Other
Intervention description(s): A single dose (24IU) of nasal spray (3 puffs of 4IU per nostril) will be administered before the assessment of the neurophysiological measures.; A single dose (24IU) of nasal spray (3 puffs of 4IU per nostril) will be administered before the assessment of the neurophysiological measures.
Other intervention name(s): Syntocinon (product code RVG 03716); Physiological water (sodium chloride (NaCl) solution)
Intervention MeSH terms: Oxytocin
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Oxytocin; Gaze processing; Interpersonal motor resonance