The presnet study is to investigate the effect of intranasal oxytocin (24 IU) treatment on modulating how human responsd to threat in a dynamic situation.

Predator-prey interactions are inherently dynamic, requiring adaptive responses from prey to survive. Altough there is eviedence for oxytocin modulating anxiety and fear responses to threats, it remains unclear whether oxytocin (OT) would modulate how humans respond to threats along the predatory imminence continuum to facilitate escape during such interactions. Our study therefore focuses on this question by combining behavioralmeasures, skin conductance response, and fMRI in a dynamic predator-prey interaction paradigm. In this double-blind, between-subject, placebo-controlled study, participants are instructed to escape by evaluating the relative distance between themselves (i.e., the prey), the predator (slow, medium and high attacking speed) and the refuge. The MRI and Biopac electrophysiological acquisition systems are used in the study to collect subjects' brain activity and skin conductance response. Participants are also asked to rate their confidence and anxiety levels during performing the task. We will aslo examine the resulted patterns of flight initiation distance (FID) and distance to refuge (DTR) when the prey fled from different predators. Scores of questionnaires including Positive and Negative Affect Schedule, State-Trait Anxiety Inventory, Beck Depression Inventory-Ⅱ, Autism Spectrum Quotient, Sensitivity to Punishment and Sensitivity to Reward Questionnaire, General Risk Propensity Scale are also collected before the experiment.

Inclusion Criteria:

• Healthy subjects without past or current psychiatric or neurological disorders

Exclusion Criteria:

• History of head injury; pregnant, menstruating, taking oral contraceptives; medical or psychiatric illness,
• The presence of metal in the body or claustrophobia.