Biological Basis of Individual Variation in Social Cooperation

The Biological Basis of Individual Variation in Social Cooperation

The project has three overall objectives. The first is to determine whether and how administration of intranasal oxytocin (OT) and intranasal vasopressin (AVP) influence cooperative decision-making and neural responses to cooperative and un-cooperative social interactions. The second is to determine whether and how intranasal vasopressin influences subjective evaluations of and neural responses to same and opposite-sex face stimuli and to determine if any of these effects persist beyond the period of AVP exposure. The third objective is to determine if intranasal OT influences empathy-related behavior and associated brain activity.

There are several objective to the study.

Objective 1: In this double-blind, placebo-controlled, pharmaco- fMRI study, men and women will be randomized to treatment with either 24 IU intranasal OT, 20 IU intranasal AVP, or placebo (PL). Approximately 40 minutes later, brain function will be imaged with fMRI as participants play an iterated Prisoner's Dilemma game with same-sex partners. The resulting data will be analyzed to investigate OT and AVP effects on cooperative behavior and the neural response to cooperative social interactions.

In addition to this cross-sectional design, a subset of participants will return on a second day for a within-subject study.

Objective 2: Men and healthy women will be randomized to treatment with either 40 IU intranasal AVP or a saline placebo approximately 30 minutes before their brain function is measured with fMRI as they view same and other-sex faces. All subjects will be scanned a second time several days later with no treatment to evaluate the persistence of AVP effects over time. The resulting data will be analyzed to investigate AVP effects on subjective evaluations and neural responses to viewing same and opposite sex faces.

Objective 3: Healthy men and healthy women will receive either 24IU intranasal OT or PL approximately 40 minutes before their brain function is measured with fMRI as they view animations of geometric shapes depicting either random movement or social interactions such as playing, chasing, fighting. All participants will receive PL on scan 1 and will be randomized to either 24IU intranasal OT or PL on scan 2. The resulting data will be analyzed to investigate OT effects on subjective evaluations and neural responses to the animations.

Inclusion Criteria:

• 18-30 years of age
• 21-30 for Faces component
• Normal or corrected-to-normal vision of 20/40
• Unmedicated depressed or anxious men between 18-22 years of age for Anxious and Depressed component

Exclusion Criteria:

• Pregnancy, recent birth, or breastfeeding
• History of seizures
• Neurological Disorder
• Current psychiatric disorder
• Previous psychiatric disorder (can be included as discretion of PI)
• Current use of psychoactive drugs
• Previous use of psychoactive drugs (can be included as discretion of PI)
• Previous head trauma (can be included at discretion of PI)
• Alcoholism or substance abuse
• Hypertension
• Cardiovascular Disease
• Nephritis
• Diabetes
• Endocrine disease or malignancy
• Asthma (can be included as discretion of PI, if episodes are infrequent, nonmedicated, and no active problems at time of study)
• Migraines (can be included as discretion of PI, if episodes are infrequent, nonmedicated, and no active problems at time of study)
• Claustrophobia (at discretion of PI)

Additional exclusion criteria for Lorazepam arm

• Acute narrow-angle glaucoma
• Compromised respiratory function (e.g. sleep apnea and chronic obstructive pulmonary disease)
• Impaired renal and hepatic function