Effects of Oxytocin Dose Frequency on Behavioral and Neural Responses

Effects of Oxytocin Dose Frequency on Behavioral and Neural Responses, and Modulation by Trait Autism and Genotype

The main aim of the study is to examine effects of different dose frequencies of repeated oxytocin administration on neural and behavioral markers of oxytocin in healthy male subjects. In addition modulatory effects of autism traits and oxytocin receptor genotype (OXTR) will be explored.

In the present study, healthy male subjects will be screened according to the study inclusion criteria. After enrollment buccal swaps will be collected for genotyping and subjects will be randomly assigned to three experimental groups that will receive treatment for 5 subsequent days: (1) placebo for five days, (2) oxytocin on days 1, 3 and 5, or (3) oxytocin for five days. Behavioral measures, task-based and resting fMRI will be assessed after the first treatment (acute effects) and the last treatment (chronic effects). The task-based fMRI will employ an implicit emotional face processing paradigm and ratings of the facial emotions will be collected after the fMRI.

Moreover, to control for potential confounding effects of relevant traits all participants will complete the following questionnaires: Interpersonal Reactivity Index (IRI),Beck depression inventory (BDI), State-Trait Anxiety Inventory (STAI). To explore potential modulatory effects of trait autism, all subjects will be administered the Autism Spectrum Quotient (ASQ) scale to assess pre-treatment autism traits.

Inclusion Criteria:

• healthy adult males

Exclusion Criteria:

• past or current psychiatric or neurological disorder head trauma substance abuse medication fMRI contraindications (e.g. metal implants)