The main aim of the study is to investigate whether intranasal oxytocin has effects on reinforcement learning under dynamic environment and interoceptive processing based on behavioral and electroencephalogram (EEG) responses.

A double-blinded, placebo-controled, between-subject design is employed in this study. In a randomized order, a total of 80 healthy males are instructed to self-administrated intranasal spray of oxytocin or placebo. (1) Participants first complete a probabilistic reward learning task 45 minutes after treatment with behavioral (response time and accuracy) and EEG data (ERP components such as FRN, ERN and P300) being collected during this task. (2) A resting-state recording and a heartbeat counting task are conducted following the learning task with ECG and EEG data being collected. Personality traits of subjects are assessed using validated Chinese version questionnaires including the Beck Depression Inventory (BDI-II), State-Trait Anxiety Inventory (STAI), Autism Spectrum Quotient (ASQ), the Cognitive Flexibility Inventory(CFI), Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), Behavioral Inhibition System and Behavioral Activation System Scale (BIS/BAS). Subjects are asked to complete Positive and Negative Affect Schedule (PANAS) when they just arrive, before and after the tasks.

Inclusion Criteria:

• Healthy subjects without any past or present psychiatric or neurological disorders.

Exclusion Criteria:

• History of brain injury medical or mental illness.