Figure 6. Schematic representation of the design of study A.

All subjects received first an administration of intranasal placebo - either by spray or nebuliser, then an intravenous administration of oxytocin (10 IU)/saline and then an intranasal administration of oxytocin (40 IU)/placebo, either by spray or nebuliser. Following drug administration, participants were placed in a Magnetic Resonance Imaging scanner for eight resting arterial spinal labeling (ASL) regional blood flow images of the brain and one resting BOLD fMRI scan. Saliva samples were collected before any drug administration (baseline) and after the scanning session (at 115 min after our last treatment administration). Plasma samples were collected before any drug administration, after any administered drug and then at several time-points during scanning session. For the current study, only time-points where saliva and plasma were concomitantly collected were considered – baseline and after scanning session. Detailed plasmatic pharmacokinetics of each route/method have been presented elsewhere (Martins et al., 2020). Adm. – administration; min – minutes; IN – Spray; NB – Nebuliser; IV – Intravenous.