View clinical trials related to Normal Physiology.
Filter by:Background: Irritability is an elevated proneness to anger. Children with irritability have difficulty tolerating frustration. They get angry and have temper outbursts more easily than their others their age. Irritability is a symptom of DMDD and ADHD. (DMDD is disruptive mood dysregulation disorder. ADHD is attention deficit/hyperactivity disorder.) Yet the reasons why some children get irritated easily are not well understood. Objective: To use brain imaging methods to study responses to frustration in youth. Eligibility: Youth aged 8 to 17 years with severe irritability (including those diagnosed with DMDD) and/or ADHD. Healthy volunteers are also needed. All participants are already enrolled in studies 02-M-0021 or 01-M-0192. Design: Participants will visit the clinic 3 times. The second and third visits will be 3 to 4 weeks apart. The first visit will be an enrollment visit. They will receive training on the tasks they will do during the study. Participants and their parents will take surveys. They will answer questions about their moods and feelings. Participants will train for an MRI scan. They will lie in a mock scanner tube and hear the noises an MRI makes. On the second and third visits, participants will have real MRI scans. They will play a computer game or watch a movie during each scan. The scans will last about 1 hour. The week after each scan, participants will wear a device on their wrist to measure their heart rate and activity level. Participants and their parent will use a smartphone to answer questions about how they are feeling and acting. Participants who do not have smartphones will be given one to use during the study.
Background: Research shows that the parietal and prefrontal areas of the brain are involved in short-term memory. Researchers want to look at the effects of transcranial magnetic stimulation (TMS) of these areas on short-term memory and brain activity. They will use functional magnetic resonance imaging (fMRI) to look at brain activity. Objective: To look at the effects of TMS on brain pathways involved in memory. Eligibility: Healthy, right-handed adults ages 18-50 Design: Participants will have 3 or 4 visits at least 1 week apart. They cannot drink alcohol for at least 48 hours before each visit. The screening visit lasts about 1 (Omega) hours. It can be combined with the first testing visit. Screening includes: - Medical history - Physical exam - Neurological exam - Urine tests - Questionnaires about being left or right handed and about their ability to imagine physical activities. The first testing visit lasts about 1 (Omega) hours and includes an MRI. For the MRI, participants lie on a table that slides into a machine. They will lie still or perform simple memory tasks on a computer screen. The second and third testing visits last about 3 hours. Participants will have: - 2 MRIs - TMS: A wire coil is held to the scalp. A brief electrical current passes through the coil to create a magnetic pulse that affects brain activity. They will perform simple memory tasks. - EMG: Small electrodes are taped to the skin to record muscle activity while they rest. After the study, participants will complete a questionnaire about any discomfort they experienced during the study.