Effect of Functional Genetic Polymorphisms on Brain Morphology and Function

Study Summary

Background: \- New research on genetics and the human genome has helped to identify certain genes that affect specific parts of the brain, including the parts that may be involved in drug use and dependency. Researchers are interested in studying both genetic information and brain activity to better understand variations in brain function among individuals. Objectives: \- To study brain activity in conjunction with specific genetic information provided by healthy volunteers including smokers, non-smokers, people with drug dependence, and those who do not have any dependence on any substance. Eligibility: \- Healthy volunteers between 18 and 50 years of age. Design: * This is an 8 10 hour study which may be completed in 1, 2, or 3 visits. * Participants will complete questionnaires about emotional and psychological responses to different situations, including stressful situations. * Participants will have a training session in a mock (fake) scanner to practice tasks to be completed in the real scanner. * Participants will have the following two types of magnetic resonance imaging (MRI) scans in one scan session of the brain: * A structural MRI scan to provide basic information about each participant's brain. * A functional MRI scanning session, in which participants will perform a memory task to provide information about brain activity. * Participants will provide blood samples for research and testing....