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Discover 23,284 clinical trials near Maryland. Find research studies in your area.
Showing 17021-17040 of 23,284 trials
NCT01031290
Background: * Cannabis, also known as marijuana, is a commonly abused drug. There is no approved medication to treat cannabis addiction. The desire to use cannabis often increases when seeing others use it or seeing pictures of it. Researchers are interested in determining which parts of the brain are active when looking at pictures associated with cannabis. * Repetitive transcranial magnetic stimulation (rTMS) uses magnetic pulses to stimulate the brain. These pulses can change activity in parts of the brain. Researchers are interested in determining whether rTMS can decrease activity in the parts of the brain that respond to cannabis, and thereby lessen cravings for cannabis. Objectives: \- To determine whether transcranial magnetic stimulation can lower craving for cannabis when people who use cannabis are shown images that increase craving. Eligibility: \- Individuals 18 years of age and older who are physically healthy and currently use cannabis (at least 3 times weekly for the past 2 years). Design: * The study will involve eight visits over 3 weeks, with each visit lasting 1 to 2 hours. * Participants will have an initial assessment about cannabis use and provide blood and urine samples before beginning the study. * Participants will have three magnetic resonance imaging (MRI) brain scans. The first MRI scan will look at the structure of the brain at rest. During the other two scans, participants will look at images related to and not related to cannabis use. * The rTMS sessions (with either actual TMS or inactive \[sham\] TMS) will be held daily for 5 consecutive days. During these testing visits, researchers will ask questions related to drug use and craving, and collect urine and breath samples for further study. * Participants will have two follow-up visits, 1 week and 2 weeks after the rTMS sessions, to evaluate memory and mood, and one final MRI brain scan at the end of the study.
NCT00095407
This study will identify the regions of the brain that are involved in personality trait knowledge-that is, what a person knows about aspects of personality such as "generous," "honest," and others. It will also examine brain areas relating to a person's knowledge of how likeable those personality traits are, being familiar with the traits, and the degree of associating such traits with one's self. There has not been any previous study, through modern imaging techniques, on the location of the brain and the concepts of personality traits. Patients ages 21 to 65 who are in good health, are right handed, and native speakers of English may be eligible for this study. Pregnant women are not eligible. There will be 200 participants involved in pencil-and-paper or computer tasks. Also, there will be three functional magnetic resonance imaging (fMRI) experiments with 32 participants. Patients may participate in up to three fMRI experiments. Patients will be recruited through NIH's Normal Control Database. They would need to have had a neuroexamination conducted by an NIH doctor within the last year. Patients will be interviewed for any medical, neurological, or psychological condition that would make it difficult to read the fMRI results. Depending on the studies that patients take part in, they will have different questionnaires to complete. They may also perform a computerized test that measures word associations. These tests will take about 1 to 2 hours. The technique of MRI uses a strong magnetic field and radio waves to obtain images of body organs and tissues. During the initial MRI scan, patients will lie still on a table that will slide into the enclosed tunnel of the scanner. They will be in the scanner not longer than 2 hours. During the procedure, they may be asked to lie as still as possible for up to 1 hour at a time. 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. Then the functional MRI (fMRI) scan will involve taking pictures of the brain while patients are performing tasks. All the tasks will be explained, and patients will have the chance to practice them before entering the scanner. For this activity, patients will be asked to make decisions about what they are seeing in the tasks presented to them. They will decide "yes" and "no" by pressing a left or right button. This scan will take about 1 hour. Afterward, patients may be asked to fill out written questionnaires or to perform reaction time tasks by using a computer. This study will not have a direct benefit for participants. However, it is hoped that information gained will enhance researchers' understanding about which areas of the brain are necessary to perform certain tasks.