General procedure
ADVERSE EVENTS, ADVERSE EFFECTS, SYNDROME, POSITIVE
On the day of the experiment, participants were required to arrive with an empty stomach, having fasted food at least 6 h and clear fluids 2 h prior to examination. Participants gave written informed consent and received written instructions. After medical examination by an anesthesiologist, an intravenous access was applied to one arm and participants were led into the MRI scanner. After participants were placed inside the MRI scanner and preparations were complete, the infusion was initialized. The anesthesiologist ensured there were no adverse events and participants were able to familiarize themselves with the substance prior to scanning to avoid anxiety-related adverse effects. The experimental task and MRI data acquisition were then initiated under continuous heart rate and oxygen level monitoring throughout the infusion. After completion of MRI data acquisition, the infusion was stopped, and participants completed the Positive and Negative Syndrome Scale (PANSS) interview with a trained blinded rater.