The Influence of Oxytocin on Socio-communicative Sensitivity

Monitoring the Influence of Oxytocin on Socio-communicative Sensitivity Using Fast Periodic Visual Stimulation

Oxytocin (OT) is a neuropeptide that acts as a neurotransmitter and neuromodulator in the brain. Previous studies have shown that intranasal administration of OT improves social cognition and behavior (e.g. emotion recognition). In the current study, we want to gain more insight into the underlying mechanisms by which OT influences emotion recognition. More specifically, we will investigate whether intranasal administration of OT enhances the salience of social (compared to non-social) information and whether it increases the neural sensitivity for subtle socio-emotional cues, by recording scalp electroencephalography (EEG) during Fast Periodic Visual Stimulation (FPVS).

The present study is a double-blind, randomized, placebo-controlled, crossover clinical trial, in which (approximately 30) neurotypical male adults (18 to 30 years old) will participate. All participants will perform two sessions (OT and placebo), separated by two weeks. For the first session, the participants are randomly assigned to the placebo or the OT condition. Syntocinon nasal spray will be used for intranasal administration. In each session, we will measure the neural salience/sensitivity for socio-emotional information, by recording EEG during FPVS. Participants simply have to press a button when the fixation cross turns red, while watching rapidly alternating visual stimuli. Starting 20 minutes after substance intake, four FPVS paradigms are administered in randomized order: A frequency-tagging FPVS paradigm, to measure the salience of social versus non-social stimuli. The oddball face detection paradigm, to assess the neural sensitivity to faces embedded in a series of objects. The oddball identity discrimination task, to examine the ability to discriminate between faces with a different identity. The oddball expression generalization task, to investigate the sensitivity for facial emotional expressions embedded within neutral faces with varying identities. After two FPVS paradigms, a four minutes resting state EEG measure will be performed. At the end of the session, emotion recognition will be measures with the Palermo matching task (65 items). The primary aim is to investigate whether the performance on each of these paradigms/tasks differs between the OT and the placebo condition. Furthermore, we want to explore whether the effect of OT is influenced by the participant's attachment style, social responsiveness, social phobia, or mood, which will be assessed via self-reported questionnaires.

oxytocin, emotion recognition, emotion processing, social salience, face processing, Electroencephalography (EEG)

Syntocinon nasal spray (40 IU/ml; oxytocin, product code RVG 03716) will be used for intranasal administration of a single intranasal dose of 24 international units (IU; 3 puffs of 4 IU per nostril)

EEG recording during simultaneous (superimposed) presentation of social stimuli (faces) and non-social stimuli (objects or houses), at a frequency of 6 and 7.5Hz, respectively (counterbalanced).

EEG recording during presentation of objects (at 6 Hz) and faces (inserted as an "oddball" every fifth image, thus at a frequency of 1.2 Hz)

EEG recording during presentation of neutral faces of the same person (same identity, presented at 6 Hz) and the face of another person (inserted as an "oddball" every fifth image, thus at a frequency of 1.2 Hz)

EEG recording during presentation of neutral faces with different identities (at 6 Hz) and faces with an emotional expression (fear, anger, happy; inserted as an "oddball" every fifth image, thus at a frequency of 1.2 Hz)

Three faces are shown on the screen. Two of them display the same emotion and the participant has to indicate which face shows a different emotion

Self-report version of the SRS. In addition to a Total score reflecting severity of social deficits in the autism spectrum, the SRS generates scores for five Treatment subscales: Social Awareness, Social Cognition, Social Communication, Social Motivation, and Restricted Interests and Repetitive Behavior.

The SAAM measures 3 different aspects of adult attachment: Security, Anxiety, Avoidance. There are 21 Likert-style questions with a score between 1 and 7 (7 for each of the three subscales).

The Positive and Negative Affect Schedule (PANAS) comprises two mood scales, one that measures positive affect and the other which measures negative affect. It consists of 20 items (10 for each subscale).

Inclusion Criteria: age between 18 and 30 years male right-handed typically developing Normal or adjusted-to-normal vision (with glasses or lenses) Exclusion Criteria: psychiatric disorder neurological disorder (e.g. epilepsy, migraine) color blindness psychoactive medication