View clinical trials related to Neural Systems.
Filter by:Background: - Cues related to past drug use induce a particular pattern of brain activation, which has been correlated with craving for cocaine in active cocaine abusers. Researchers are interested in determining the role of the brain chemical dopamine in cue-elicited as well as spontaneous craving for cocaine. - To study the role of dopamine in cocaine craving, researchers will use positron emission tomography (PET) to compare the neural reactions of cocaine users with those of non-substance-abusing healthy volunteers. Researchers hope that the data gathered from this study will lead to the development of more effective anti-craving medications. Objectives: - To clarify the role of dopamine in cue-elicited responses that contribute to cocaine abuse. - To determine if PET results of this study differ with various means of administering PET chemicals. Eligibility: - Individuals 21 to 44 years of age who are either current cocaine users (at least twice per week) or healthy volunteers without a history of drug abuse. Design: - Cocaine-using participants will enter the inpatient clinical research ward at the National Institute on Drug Abuse (NIDA) Addiction Research Center for 2 nights before the day of the study. In addition, these participants will stay overnight at NIDA the evening after each PET session and will be discharged the following day. Cocaine-using participants will be required to perform a balance test before the study to provide a baseline response in case they require anti-anxiety medications to cope with the effects of the study. - Control subjects will not be required to stay overnight and will arrive as outpatients for the PET session. All participants will be required to abstain from alcohol and caffeine consumption from midnight before each study session, and will not be permitted to smoke on the day of testing. - - On the day of the study, participants will undergo a practice session to set up the PET scanning equipment. Following the practice session, participants will be shown video recordings of images that are related to nature (e.g., seashells) or to drug abuse (e.g., drug paraphernalia). Participant reactions will be studied through the PET monitoring, and the study will be conducted in two separate PET sessions with a break in between. Individuals in the cocaine-using group may receive anti-anxiety medication if the stimulus cues increase anxiety related to cocaine craving. - Different groups of participants will receive different methods of PET chemical administration, and researchers will compare these methods.
This study is directed toward a better understanding of how the brain regulates emotions and social and antisocial behavior. It will look at the use of the orbital frontal cortex and amygdala of the brain. Brain changes are involved in solving conflicts and the feelings that such conflicts produce. Conflicts may occur with other people or with general social rules. The researchers' expectations are that the findings will be useful in developing therapies that may improve people's ability to solve social conflicts and reduce antisocial behavior. Adults ages 20 to 50 years of age with psychopathy and a second set of comparison adults, all of whom have been released from the Fairfax County Adult Detention Center, may be eligible for this study. The neurocognitive component of the study, the one pertaining to performance of various tasks, will involve 20 adults with psychopathy and 20 comparison adults. The neuroimaging component, in which a magnetic resonance imaging (MRI) scan is used, will involve 18 adults and 18 comparison adults. Two visits by participants will be entailed. At the first visit, patients will undergo the following procedures and tests: - Physical examination - Test of vital signs, lying and standing. - Electrocardiogram. - Collection of blood for chemistry and hematology. - Urinalysis and liver function tests. - Screen for HIV and hepatitis. - Pregnancy test, if applicable, at the first visit and at all further visits. Depending on the group to which they are assigned, at the second visit, patients will undergo an MRI scan or take part in a variety of computer-based tasks to measure different forms of thinking skills, emotional responses, and decision making. During the MRI scan, patients will lie still on a table that will slide into the enclosed tunnel of the MRI scanner. They will be asked to lie as still as possible. As the scanner takes pictures, patients will hear knocking or beeping sounds, and they will wear earplugs to reduce the noise. Patients will be able to communicate with the MRI staff at all times during the scan, and they may ask to be moved out of the machine at any time. While lying in the MRI scanner, patients will be asked to perform tasks presented via a screen. These tasks will involve looking at pictures or words, and patients will be asked to make decisions about the pictures. The MRI scan will take no more than 2 hours. In regard to the computer-based tasks that participants will perform, the tasks are often games presented on a computer. Via computer, or on paper, there may be presentations of pictures that bring about an emotion. There will be no direct treatment or therapeutic benefits to participation in this study. However, the knowledge gained may help people in the future.