Advanced Functional and Structural MRI Techniques for Neuropharmacological Imaging

Background: \- Functional and structural magnetic resonance imaging (MRI) techniques have allowed researchers to map and study how the brain works when at rest and when engaged in specific tasks. MRI scans have provided more information about how drugs affect the brain, and about how drug addiction changes the brain and influences behavior, mood, and thinking processes. To better understand the underlying mechanism of drug addiction and to develop strategies for more effective treatment, researchers are interested in developing new MRI techniques to study the effects of addiction on the brain. Objectives: \- To develop new functional and structural MRI techniques, and to evaluate their potential use in brain imaging studies related to addiction. Eligibility: * Individuals between 18 and 80 years of age. * Participants may be smokers or nonsmokers, and may use drugs or not use drugs. Design: * During the initial screening, participants will complete questionnaires about family and personal history, drug use, and other information as required by the researchers. Participants who will be asked to complete tasks during the MRI scan will be shown how to perform these tasks before the scanning session. * Before each study session, participants may be asked to complete some or all of the following: questions about their drug use during the last week, a breathalyzer test, a urine drug-use assessment, a urine pregnancy test, or a measure of carbon monoxide. Participants will also provide blood samples before the start of the scan. * For each scanning session, participants will have an MRI scan that will last approximately 2 hours. * MRI scans may include specific tasks to be performed during the scan, or an experiment that studies the brain's response to carbon dioxide.