Primary Outcomes

Description: Functional magnetic resonance imaging will be performed to measure the BOLD signal in response to emotional face stimuli. The investigators specifically plan to investigate neural responses to emotional faces in amygdala and striatal subregions. The BOLD signal in response to fearful faces relative to neutral faces and happy faces relative to neutral will be compared between the oxytocin and placebo sessions. To examine effects of the Receptor for Advanced Glycation End Products (RAGE), analyses of variance (ANOVAs) with the between subjects factor RAGE polymorphism (-374 T/A: rs1800624; TT vs. TA/AA) will be conducted on the second level. For analyses of fMRI data, default procedures of the software SPM12 will be adapted for ultra-high-field imaging. The family-wise error rate will be used to correct p-values for multiple comparisons and p < .05 will be considered significant.

Description: Functional magnetic resonance imaging will be performed to measure the blood-oxygen-level dependent (BOLD) signal in a flight initiation distance (FID) task, involving fast-, medium- and slow-attacking virtual predators that elicit distinct activations in the reactive and cognitive fear circuits. BOLD signals to different predator velocities will be analyzed. Analyses will focus on regions-of-interest associated with the processing of cognitive fear (vmPFC, PCC, hippocampus, and basolateral amygdala) and reactive fear (midbrain PAG, central amygdala, hypothalamus, and the MCC) and the reward system (striatum). To examine effects of the Receptor for Advanced Glycation End Products (RAGE), ANOVAs with the between-subject factor RAGE polymorphism (-374 T/A: rs1800624; TT vs. TA/AA) will be conducted on the 2nd level. For the fMRI data, default procedures of the software SPM12 will be adapted for ultra-high-field imaging.

Description: Behavioral data of the FID task (flight distance and difficulty ratings ) will be analyzed using mixed ANOVAs in the software SPSS with treatment (oxytocin vs. placebo) as within-subject factor and RAGE polymorphism (TT vs. TA/AA) as between-subject factor. Post-hoc t-tests will be Bonferroni-corrected. Behavioral data will be correlated with fMRI data of the FID task.

Secondary Outcomes

Description: Blood samples will be collected before and after the nasal spray administration to assess changes in oxytocin concentrations. Oxytocin concentrations will be analyzed using mixed ANOVAs in SPSS with time (pre vs. post) and treatment (oxytocin vs. placebo) as within-subject factors and RAGE polymorphism (TT vs. TA/AA) as between-subject factor.

Description: Blood samples will be collected before the nasal spray administration to assess the RAGE (extracellular domain) concentration in blood plasma. RAGE concentrations will be compared between RAGE polymorphisms (TT vs. TA/AA) with independent t-tests. Furthermore, the investigators plan to examine if the RAGE concentration moderates the effects of oxytocin on primary and secondary outcomes.