Effects of Oxytocin on Reinforcement Learning

The Effects of Intranasal Oxytocin on Reward Sensitivity and Performance Monitoring During Reinforcement Learning: an ERP Study

The main aim of the study is to investigate whether intranasal oxytocin (24IU) influences reward sensitivity and performance monitoring during reinforcement learning.

A double-blind, within-subject, placebo-controlled pharmacological EEG design will be employed. A total of 35 healthy male subjects will be recruited which will receive either intranasal placebo or oxytocin (24IU) on two separate study days (order counter-balanced, washout period at least 2 weeks). 45 minutes after treatment subjects will undergo a probabilistic feedback reinforcement learning paradigm with concurrent EEG acquisition. During the paradigm subjects will learn the reward probabilities of two different visual stimuli from probabilistic feedback provided by social stimuli (positive, negative emoticon). The paradigm includes an initial acquisition phase and a subsequent test phase.

Participants first receive oxytocin (24 IU). After a washout period of 2 weeks, they receive placebo.

Participants first receive placebo. After a washout period of 2 weeks, they receive oxytocin (24 IU).

Feedback Related Negativity (FRN): a negative ERP component evoked by negative feedback relative to positive feedback during the acquisition phase will be compared between the oxytocin and placebo treatment conditions.

Error Related Negativity (ERN): a negative ERP component evoked by incorrect responses relative to correct responses during the test phase will be compared between the oxytocin and placebo treatment conditions.

Correct responses are defined as choices of the stimulus associated with higher probability positive feedback during the acquisition phase. Effects of treatment will be analyzed by comparing the performance between the two treatment conditions.

Behavioral index: Response accuracy to stimuli associated with highest probability positive feedback during the test phase

Correct responses are defined as choices of the stimulus associated with highest probability positive feedback as learned in the acquisition phase. Effects of treatment will be analyzed by comparing the performance between the two treatment conditions.

Response accuracy avoiding stimuli associated with highest probability negative feedback in the test phase.

Correct responses are defined as avoidance choices of stimuli associated with highest probability negative feedback as learned in the acquisition phase. Effects of treatment will be analyzed by comparing the performance between the two treatment conditions.

Response accuracy in response to superior stimuli associated with relative higher probability positive feedback in the test phase.

Correct responses are defined as choices of the stimulus associated with higher probability positive feedback. Note that stimuli pairs in this measurement are all associated with positive feedback. Effects of treatment will be analyzed by comparing the performance between the two treatment conditions.

Response accuracy avoiding stimuli associated with higher probability negative feedback in the test phase.

Correct responses are defined as avoidance choices of stimuli associated with higher probability negative feedback. Note that stimuli pairs in this measurement are all associated with negative feedback. Effects of treatment will be analyzed by comparing the performance between the two treatment conditions.

Inclusion Criteria: Age between 18-30 Male sex Right handedness Exclusion Criteria: History of brain injury Current or history of psychiatric, neurological or internist disorder Current or regular use of medication, psychotropic substances, including nicotine Contraindications for Oxytocin