State-dependent Interoception, Value-based Decision-making, and Introspection

Background: Negative emotional states can affect a person s behavior as they make decisions. For example, hunger may make people more impatient; they may then make riskier choices. Other negative emotional states that can change behavior include stress, pain, and sadness. By learning more about how emotions affect thinking and behavior in healthy people, researchers hope to better understand how to identify and treat people with mental disorders. Objective: To learn how negative emotions affect the brain and decision-making behavior. Eligibility: Healthy people aged 18 to 55 years. Design: Participants will have 3 clinic visits in 3 weeks. Participants will fill out questionnaires. They will be asked about their personal history, their personality, and state of mind. For 2 visits, participants will be assigned to different groups. Each group will experience 1 type of emotional stressor: Some participants will watch a video. Some will have to do arithmetic problems. Some will have heat applied to an arm or leg. Some will experience cold by immersing their hand in ice water. For a snack craving test, some will be tempted by food after a 4-hour fast. During these tests, participants will have sensors attached to their bodies. They will be videotaped. Saliva samples will be collected. After the stressors, participants will do tasks on a computer. They will need to make choices. Some participants will perform these decision-making tasks while lying in a brain scanner for functional magnetic resonance imaging. The brain scan involves lying on a table that slides into a cylinder that takes images of the brain. ...