Healthy Volunteers

Background: Transcranial magnetic stimulation (TMS) uses magnetic pulses to affect brain activity. A type of TMS called theta burst stimulation (TBS) is approved to treat people with major depression. Researchers have developed a new form of TBS called high-density TBS (hdTBS). They hope hdTBS will work better than TBS. But first they need to test the new treatment in healthy adults. Objective: To test hdTBS in healthy adults. Also, to compare the aftereffects of hdTBS and TBS. Eligibility: Healthy adults aged 22 to 60 years. Design: Participants will have 4 clinic visits over about 3 to 4 weeks. They must abstain from drugs and alcohol and limit caffeine before visits. At their first visit, participants will be oriented to TBS. They will wear a cap and earplugs. A device with round coils will be placed near their head. When a brief electric current passes through the coil, it generates a magnetic pulse that stimulates the brain. Participants may feel a pulling sensation on the skin under the coil. Their fingers may move involuntarily. At their next 3 visits, participants will receive either TBS or sham TBS. A sham TBS uses a low magnetic field to minimize the effects of the treatment. Participants will have up to 9 electrodes placed on 1 arm. These electrodes will measure the electrical activity in their muscles. Each TBS session will be videotaped. At every visit, participants will answer questions about their health, including substance use. They will perform 2 tasks to test their thinking skills. They will perform a test on a computer to test their reaction time....

Background: Opioid drugs are often prescribed for acute and chronic pain. But these drugs are addictive, and they lead to more than 14,000 overdose deaths in the United States each year. Researchers want to find new drugs that relieve pain but are not addictive. This study will test whether a single dose of an experimental drug called (2R,6R)-hydroxynorketamine (HNK) can help reduce short term pain in healthy adults. HNK is related to ketamine. Studies suggest HNK might be as effective as ketamine at reducing pain but that it might have fewer side effects. In this study we will test how HNK affects pain and emotion. The results of this study may help us understand whether HNK has pain relieving effects and how it works in the brain, which could inform future pain treatments. Objective: To test the study drug \[(2R,6R)-hydroxynorketamine (HNK)\] for treating acute pain in healthy people. Eligibility: Healthy people aged 18 to 60 years. Design; Up to 92 healthy volunteers between 18 and 60 years old without chronic pain or psychiatric conditions will participate in the study. The study will take place at the NIH Clinical Center in Bethesda, Maryland. Each participant s involvement will last up to two months. The overall study is expected to last about three years (36 months). The study has 2 parts. In part 1, participants will have up to 2 clinic visits. They will be screened and have blood draws to make sure they're eligible for the study. They will complete sensory testing and have MRI brain scans. Sensory testing involves feeling and rating painful and non-painful sensations. These may include hot or cold temperatures, pinches or squeezes, and being touched with brushes or pinpricks. Eligible participants will have an imaging scan that shows brain activity: During the scan, they will rate heat, hear pleasant or unpleasant sounds, and view unpleasant or pleasant pictures. After completing part 1, eligible participants will be invited to part 2, which includes overnight stays at NIH. In part 2, participants will be assigned to either a treatment group or a no-treatment group. The treatment group will have 2 overnight visits of 2 nights each. The visits will be 1 to 3 weeks apart. For one of the visits, treatment group participants will receive the study drug HNK. For the other visit, they will receive a placebo. A placebo looks just like the study drug but contains no medicine. HNK and placebo are given through a tube inserted into a vein in the arm. The sensory tests, blood draws, and MRI scans will be repeated at each visit. Participants will not be told whether they got the drug or placebo on each visit. The nontreatment group will have 1 overnight visit. They will not receive the drug or placebo. The sensory tests, blood draws, and MRI scans will be repeated. Participants cannot drink alcohol, use recreational drugs, or take certain other kinds of medicine or supplements during the study.

This study will evaluate safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of single ascending doses (SAD) (Part 1a), multiple ascending doses (MAD) (Part 1b), and the food effect (Part 1c) of RO7763505 in healthy adult participant. In Part 2, the safety, tolerability, PK and PD of multiple doses of RO7763505 in participants with stable coronary artery diseases (CAD).

The main purpose of this study is to evaluate how well LY4178256 is tolerated and what side effects may occur in healthy participants. Blood tests will be performed to check how much LY4178256 gets into the bloodstream and how long it takes the body to eliminate it. For each participant, the study will last about 7 months and will include either 7 or 12 visits depending on the assigned treatment.

Background: Opioid drugs are often prescribed for acute and chronic pain. But these drugs are addictive, and they lead to more than 14,000 overdose deaths in the United States each year. Researchers want to find new drugs that relieve pain but are not addictive. This study will test whether a single dose of an experimental drug called (2R,6R)-hydroxynorketamine (HNK) can help reduce short term pain in healthy adults. HNK is related to ketamine. Studies suggest HNK might be as effective as ketamine at reducing pain but that it might have fewer side effects. In this study we will test how HNK affects pain and emotion. The results of this study may help us understand whether HNK has pain relieving effects and how it works in the brain, which could inform future pain treatments. Objective: To test the study drug \[(2R,6R)-hydroxynorketamine (HNK)\] for treating acute pain in healthy people. Eligibility: Healthy people aged 18 to 60 years. Design; Up to 92 healthy volunteers between 18 and 60 years old without chronic pain or psychiatric conditions will participate in the study. The study will take place at the NIH Clinical Center in Bethesda, Maryland. Each participant s involvement will last up to two months. The overall study is expected to last about three years (36 months). The study has 2 parts. In part 1, participants will have up to 2 clinic visits. They will be screened and have blood draws to make sure they're eligible for the study. They will complete sensory testing and have MRI brain scans. Sensory testing involves feeling and rating painful and non-painful sensations. These may include hot or cold temperatures, pinches or squeezes, and being touched with brushes or pinpricks. Eligible participants will have an imaging scan that shows brain activity: During the scan, they will rate heat, hear pleasant or unpleasant sounds, and view unpleasant or pleasant pictures. After completing part 1, eligible participants will be invited to part 2, which includes overnight stays at NIH. In part 2, participants will be assigned to either a treatment group or a no-treatment group. The treatment group will have 2 overnight visits of 2 nights each. The visits will be 1 to 3 weeks apart. For one of the visits, treatment group participants will receive the study drug HNK. For the other visit, they will receive a placebo. A placebo looks just like the study drug but contains no medicine. HNK and placebo are given through a tube inserted into a vein in the arm. The sensory tests, blood draws, and MRI scans will be repeated at each visit. Participants will not be told whether they got the drug or placebo on each visit. The nontreatment group will have 1 overnight visit. They will not receive the drug or placebo. The sensory tests, blood draws, and MRI scans will be repeated. Participants cannot drink alcohol, use recreational drugs, or take certain other kinds of medicine or supplements during the study.

Background: Transcranial magnetic stimulation (TMS) uses magnetic pulses to affect brain activity. A type of TMS called theta burst stimulation (TBS) is approved to treat people with major depression. Researchers have developed a new form of TBS called high-density TBS (hdTBS). They hope hdTBS will work better than TBS. But first they need to test the new treatment in healthy adults. Objective: To test hdTBS in healthy adults. Also, to compare the aftereffects of hdTBS and TBS. Eligibility: Healthy adults aged 22 to 60 years. Design: Participants will have 4 clinic visits over about 3 to 4 weeks. They must abstain from drugs and alcohol and limit caffeine before visits. At their first visit, participants will be oriented to TBS. They will wear a cap and earplugs. A device with round coils will be placed near their head. When a brief electric current passes through the coil, it generates a magnetic pulse that stimulates the brain. Participants may feel a pulling sensation on the skin under the coil. Their fingers may move involuntarily. At their next 3 visits, participants will receive either TBS or sham TBS. A sham TBS uses a low magnetic field to minimize the effects of the treatment. Participants will have up to 9 electrodes placed on 1 arm. These electrodes will measure the electrical activity in their muscles. Each TBS session will be videotaped. At every visit, participants will answer questions about their health, including substance use. They will perform 2 tasks to test their thinking skills. They will perform a test on a computer to test their reaction time....

Background: The Laboratory of Immune System Biology (LISB) works with other labs at the National Institutes of Health. They study how parts of living things come together to make a whole. LISB designs and improves research tests on human samples like blood and cells. In order to do its work, LISB needs to have a lot of these samples available. Objective: To collect biological specimens to use for designing and improving research tests. Specimens include blood, stool, saliva, and skin/mucosal swabs. Eligibility: Healthy people ages 3-80 Design: Participants will be screened with an interview about their general health and their medical history. They will have a physical exam and blood tests. If the results of the screening are normal, participants will be asked to give one or more of these samples: Blood will be drawn from an arm vein with a needle and syringe. Mucus and skin will be collected by rubbing the area with a cotton swab. The areas may include the top of the tongue, inside the cheek, nostrils, behind the ear, elbow pit, or vagina. Participants will spit into a tube to collect saliva. Participants will pass stool into a plastic container that fits in the toilet under the seat. They will get sampling kits and instructions. Over the next 5 years, if more samples are needed, participants will be contacted to set up another visit to the NIH. These visits will each take about 1 hour. About every 2 years, when participants come to NIH for a visit, extra blood will be collected. It will be tested for HIV and hepatitis B and C. ...

Background: \- Studies show that many factors affect children's eating behavior and health. These include sleep, mood, thinking skills, and genetics. Studying children over time may identify children at higher risk for eating-related health concerns. Objective: \- To understand how genes and environment influence eating behavior and health over time. Eligibility: \- Children ages 8-17 in good general health. Design: * Screening visit 1: Medical history, physical exam, body measurements, and questions. * 14 days: Participants will wear a wrist monitor and answer smartphone prompts about eating and mood. They may give a stool sample. * Screening visit 2: * Body measurements. * Saliva, urine, and blood samples. * Heart tests. * Meals provided (after fasting overnight). * Questionnaires and interview. * Behavior, thinking, and exercise tests. * X-ray of left wrist and full body.\<TAB\> * Some parents may have medical history, physical exam, and questions at screening visits. They may answer questions at the yearly visits. * Participants will have up to 6 yearly visits. They will give a urine sample and body measurements, and repeat the X-rays. They will have questions and behavior and thinking tasks. They may give stool samples. Visits will range from 3 to 8 hours. * Participants may choose to participate in other studies: * Stress and Hormones, 1 visit: While resting, participants will give saliva samples and have their heart monitored. Then they will do math. They will repeat the resting part, then do a computer task. * Brain Imaging, 2 visits: Twice, participants will perform tasks with a magnetic cone on their head then answer questions. Once, they will have an MRI, lying still in a scanner with a coil on their head. Before the first visit, participants will collect at-home saliva samples once a day for three days. During both visits, participants will perform tasks and answer questions that gauge their thinking skills and mood. * Experiment 3 (sleep/fatigue): Participants will complete 2 additional visits. During these visits, participants will complete a task on the computer for 2 hours, or watch a movie for two hours. After completion of the task/movie, they will answer questions and be provided with food. Participants will be compensated for the time and inconvenience involved with completing study procedures. ...

The purpose of the trial is to evaluate the pharmacokinetics, safety, and tolerability of TEV-56286 at different doses. The main objective is to describe how TEV-56286 is absorbed, distributed, and removed from the body (the pharmacokinetics) following administration of TEV-56286 in single doses of increasing amounts and multiple doses in healthy participants. A secondary objective is to assess the safety of TEV-56286 and how well it is tolerated. The estimated duration for participants in Part 1 with Single Ascending Dose is approximately 58 days; including up to 45 days of screening, a 4-day in-clinic period, and follow-up 8+/-1 days post discharge from the clinical unit. The estimated duration for participants in Part 2 with Multiple Dose is approximately 64 days; including 45 days of screening, a 10-day in-clinic period, and follow-up 8+/-1 days post discharge from the clinical unit.

This study is designed to evaluate the relative bioavailability (rBA) of multiple test tablet formulations of BMS-986435 compared to an equal dose of the BMS-986435 reference tablet formulation. The effect of food on the selected BMS-986435 tablet formulation will also be evaluated.

Background: There are no good treatments for people considering suicide. Researchers want to study suicide with questions, blood tests, brain imaging, and sleep studies. They hope to better understand suicide, so they can help suicidal people. Objective: To understand what happens in the brain when someone has thought about or attempted suicide. Eligibility: Group 1: Adults ages 18 70 who have thought about or attempted suicide recently Group 2: Adults ages 18 70 who have thought about or attempted suicide in the past Group 3: Adults ages 18 70 who have depression or anxiety, but have never thought about suicide Group 4: Healthy volunteers the same ages. Design: Participants will be screened in another protocol. Adults who have recently thought about or attempted suicide must be referred by a doctor. They may do up to 3 phases of this study. Groups 2, 3 and 4 will do only Phase 1 and will not get ketamine. Phase 1: 1 week in hospital. Participants will have: Physical exam. Questions about thoughts and feelings. Thinking and memory tests and simple tasks. Blood and urine tests. Two MRI scans. Participants will lie on a table that slides into a metal cylinder that takes pictures. They will have a coil over their head and earplugs and do a computer task. Sleep test. Disks and bands will be placed on the body to monitor it during sleep. Magnetic detectors on their head while they perform tasks. A wrist monitor for activity and sleep. Lumbar puncture (optional). A needle will collect fluid from the back. Shock experiments (optional). Participants will observe pictures and sounds and feel a small shock on the hand. Phase 2: 4 days in hospital. A thin plastic tube will be placed in each arm, one for blood draws, the other to get the drug ketamine once. Participants will repeat most of the Phase 1 tests. Phase 3: up to 4 more ketamine doses over 2 weeks. Participants will have follow-up calls or visits at 6 months and then maybe yearly for 5 years.

Background: \- National Institute on Aging researchers are looking at studies that require large numbers of white blood cells for lab use. Standard blood samples do not provide enough white blood cells for these studies. Researchers want to use cytapheresis to collect white blood cells from volunteer donors. This procedure can collect larger amounts of white blood cells and reduce the amount of fluid and other cells that are lost. Objectives: \- To use cytapheresis to collect white blood cells for study. Eligibility: \- Healthy blood donors at least 18 years of age. Design: * Participants will be screened according to the usual blood donation procedures. * Participants will provide white blood cells through cytapheresis. The blood cells will be collected in a machine that separates the white blood cells from the rest of the blood. The rest of the blood will be returned to the donor. * Participants may have this type of donation every 56 days (six times per year). They will be asked to become a repeat donor. A donation schedule may be set up. * Once a year, participants will have blood tests to continue to be eligible as a donor.

This study looks at how to reduce nausea and vomiting in people taking KarXT which is used to treat mental health conditions like schizophrenia. KarXT can cause stomach-related side effects, especially in the first couple of weeks. In this study, healthy volunteers will take KarXT along with anti-nausea medication, either regularly (to prevent symptoms) or as needed. The goal is to see how well these strategies help reduce nausea and vomiting and how safe the combination is. The results will help doctors better manage side effects and make treatment more comfortable for patients starting KarXT.

There are a number of disorders of the brain that have limited treatment options, such as chronic pain, addiction, and major depression. A new technology has emerged in the last decade known as transcranial focused ultrasound, which can deliver focused acoustic signals through the skull to modulate brain activity over a small region, including structures deep in the brain. This has resulted in many ongoing clinical trials for various disorders, but there is still a lack of understanding of the optimal sonication parameters for increasing versus decreasing brain activity. The investigators aim to address this open question by sonicating the primary visual cortex and primary auditory cortex in human with a range of sonication parameters. These brain structures were chosen to target because they are expected to elicit perceptual responses in the subject (i.e., the subject will report visual and auditory perception during sonication), allowing the experimenters to infer directly the extent to which neural signals can propagate through the visual and auditory systems in a way that is sufficient to produce conscious perception. Such findings have applications not only in clinical treatments, but also in the fundamental science of the neural basis of sensory perception. Previous work has shown that sonicating the visual cortex in humans can elicit visual perception, but the ultrasonic system in prior work did not have the focusing capabilities that will be employed in this study. At the end of this study, the investigators will have determined the optimal sonication parameters that can elicit neural responses over a small volume over sensory cortex, which can be inferred from visual percepts being localized in space (e.g., a bright spot as opposed to a diffuse light), and auditory percepts that sound like pure tones rather than a broad set of frequencies (e.g., sounding like white noise or static).

This Phase 1 open-label study enrolls 24 healthy Chinese adults to investigate the pharmacokinetics, safety and tolerability of oral IPG1094 tablets. The trial includes two parts. Part A (12 participants) uses a crossover design to explore the impact of food on a single 200 mg dose of IPG1094; participants will receive the drug under fasting and post-meal conditions on separate days, with intensive blood sampling for PK analysis. Part B (12 participants) evaluates multiple-dose PK, where participants take 200 mg IPG1094 twice daily for 10 days to observe drug exposure and accumulation. All participants will undergo comprehensive safety checks such as lab tests, ECG and adverse event monitoring during screening, treatment and post-dosing follow-up. No placebo or blinding is applied in this study.

This study is being done to understand how much of the medicine (CDR132L) enters the bloodstream after injection under the skin compared to injection into a vein in healthy people. This will help us find the best way to give the medicine to people living with heart failure. The study will assess what the body does to the medicine, and how safe it is.

This randomized, double-blind, crossover trial (Phase IV) aims to compare the absorption of a novel permeability-enhanced oral vitamin B12 formulation (Ampli-B) versus standard oral vitamin B12 in 12 healthy adults aged 50 years and older. Each participant receives a single dose of each formulation in randomized sequence, separated by a minimum 10-day washout. The primary outcome is time to peak serum concentration (Tmax) of total and active vitamin B12 (holotranscobalamin). Secondary outcomes include Cmax and AUC parameters.

The purpose of this study is to evaluate the intra-observer and inter-observer reliability of the Kinovea video analysis software in measuring knee and hip angles during the sit-to-stand movement. Participants will perform sit-to-stand tasks while being video-recorded. The recorded movements will be analyzed using the Kinovea software to determine the consistency and reliability of joint angle measurements.

The goal of this randomized cross-over trial is to learn about the effect of a single bout of 20-min mindfulness-based high-intensity interval training (MF-HIIT), MF-only, and HIIT-only in relative to sitting rest on executive function (EF) in 10-12 years old children. The main question it aims to answer are: Question 1: Whether a single bout of 20-min MF-HIIT has larger beneficial effect on EF performance than that following a 20-min session of MF-only and HIIT-only in relative to the sitting rest Question 2: Whether a single bout of 20-min MF-HIIT has a larger beneficial effect on brain functioning, as measured by the N2 and P3 components of event-related potential (ER) during EF performance than that following a 20-min session of MF-only and HIIT-only in relative to the sitting rest Participants will visit the laboratory on 5 separate days (\> 2-day washout between days) in which they have not previously participated in structured physical activities. Participants will complete the testing and/or receive treatments below: Day 1: * Kaufman Brief Intelligence Test (KBIT) to assess intelligence quotient * Treadmill-based exercise test to measure cardiorespiratory fitness (maximum oxygen consumption) Days 2-5 * Each day, participants will complete each of the four intervention conditions (MF-HIIT, MF-only, HIIT-only, sitting) * Participants' heart rate and self-reported affect and rating of physical exertion will be measured * Participants will complete a modified flanker task and a task-switching task to assess inhibitory control and cognitive flexibility * Participants will wear an EEG cap to measure the N2 and P3 components of the event-related potential during the inhibitory control and cognitive flexibility performance Researcher will compare the cognitive outcome measures following the MF-HIIT, MF-only, and HIIT-only conditions with the sitting condition to see if MF and HIIT has beneficial effects on children's EF. Further, researcher will compare the cognitive outcome measures following the MF-HIIT compared with MF-only and HIIT-only conditions to see if combining MF with HIIT has greater beneficial effects on children's EF than MF and HIIT alone.

The goal of this randomized controlled trial is to learn about the effect of a 12-week school-based intervention combining mindfulness with high-intensity interval training (MF-HIIT), MF-only intervention, and HIIT-only intervention in relative to sedentary activities on executive function (EF) in 8-12 years old children. The main question it aims to answer is whether a 12-week school-based MF-HIIT intervention has larger beneficial effect on EF performance than that following a 12-week school-based MF-only and HIIT-only in relative to the sedentary activities. Multiple cohorts of participants will be recruited to participate this one-semester study, including the pretest, intervention, and posttest phases. During the pretest phase, participants an their parents will complete the following 1. Kaufman Brief Intelligence Test (KBIT) to assess intelligence quotient 2. Fitnessgram test to assess aerobic capacity, muscle endurance, flexibility, and body mass index 3. Child and Adolescent Mindfulness Measure (CAMM) questionnaire to assess dispositional mindfulness 4. Computerized tasks to assess EF 5. Parent-reported demographic and health information Following the pretest phase, participants will receive the 12-week classroom-based intervention, with the classroom as the intervention unit. Following the intervention and during the posttest phase, participants will complete the fitness, measures, EF measures, and dispositional mindfulness measure again. Researcher will compare the EFn outcome measures following the MF-HIIT, MF-only, and HIIT-only interventions with the sedentary activity intervention to see if MF and HIIT has beneficial effects on children's EF. Further, researcher will compare the EF measures following the MF-HIIT compared with MF-only and HIIT-only interventions to see if combining MF with HIIT has greater beneficial effects on children's EF than MF and HIIT alone.

The purpose of this protocol is to allow for the careful screening of patients and healthy volunteers for participation in research protocols in the Experimental Therapeutics and Pathophysiology Lab (ETPB) at the National Institute of Mental Health (NIMH) and for the collection of natural history data. In addition the protocol will allow clinicians to gain more experience in the use of a variety of polysomnographic and high-density EEG recordings. Subjects in this protocol will undergo an evaluation which may include: a psychiatric interview; a diagnostic interview; rating scales; a medical history; a physical exam; brain magnetic resonance imaging (MRI); electroencephalography (EEG); electrocardiography (EKG), magnetoencephalography (MEG); blood, saliva and urine laboratory evaluation; and a request for medical records. Subjects may also be asked to complete questionnaires about attitudes towards research and motivation for research participation. The data collected may also be linked with data from other mood and anxiety disorder protocols (e.g., brain imaging, DNA, psychophysiology tests, treatment studies, etc) for the purposes of better understanding the diagnosis, pathophysiology, and treatment response of patients with mood disorders. Parents of minors will be interviewed. Upon conclusion of the screening process, subjects will either be offered participation in a research protocol and will sign the appropriate informed consent, or will be considered not appropriate for participation in research and will be referred back into the community. The current protocol thus serves as an entry point for individuals with mood or anxiety disorders or healthy volunteers to enter NIMH IRB approved ETPB protocols.

The objective of this study is to assess the safety, tolerability, pharmacokinetics, and immunogenicity of single and multiple doses of ABBV-313 in healthy adult participants.

This study aims to compare the bioavailability of Dimotec 1000 mg film-coated tablet (Test; Keri Pharma Hungary Kft.) with Detralex 1000 mg film-coated tablets (Reference; Les Laboratoires Servier Industrie, France) in healthy adult human participants under fed conditions. The study will also evaluate the safety and tolerability of a single dose of the investigational products.

Background: Artificial sweeteners like sucralose are found in many foods and drinks. Sucralose might affect hormones and cause health changes. Objective: To see if sucralose changes how medicines are absorbed and processed, how hormones are secreted, gut bacteria, and how fat cells are metabolized. Eligibility: People ages 18-60 who: * Are black or Hispanic * Weigh more than 110 pounds * Have a body mass index of 25-40 * Do not have a condition that requires drug treatment Design: Participants will be screened with: * Medical history * Physical exam * Blood, heart, and urine tests Participants must not eat or drink anything with artificial sweeteners throughout the study. Over 7 days, Participants will answer questions, and give daily urine samples and 1 stool sample. Participants will repeat these throughout the study. Overnight Visit 1: participants will fast starting the night before. They will get breakfast at the visit. The visit includes: * An IV will be placed in the arm. Participants will get 2 tablets of medicines. Blood will be drawn several times over 24 hours. * A piece of fat tissue may be taken from the abdomen (biopsy). * Participants will have a sweet drink. Blood samples will be taken over 2 hours. Then participants will be randomly assigned to take either a sucralose capsule or placebo. They will take it twice a day for 2 weeks. They will complete two 24-hour food diaries. Overnight Visit 2 repeats Visit 1 except the biopsy. Then participants will take the capsules for another 2 weeks. Overnight Visit 3 repeats Visit 1. Participants may be contacted by phone within 4 weeks after they finish.

Background: \- Biomarkers are substances in people s blood and tissues. They help researchers understand diseases and signs of aging. Scientists want to do more research on biomarkers to find ways to improve quality of life in old age. Objective: \- To learn more about biomarkers and their relationship to aging. Eligibility: \- Adults at least 20 years old who weigh at least 110 pounds and have a body mass index below 30. They must agree that their genetic samples can be collected, studied, and stored. Design: * Participants will be screened with medical history, physical exam, EKG and blood and urine tests. * Participants will have 3-day visits. They will return every 2 years. * All visits include: * Blood and urine collection * Physical performance tests * Health questionnaires * Memory and problem-solving tests * Magnetic Resonance Imaging (MRI) and Computerized Tomography (CT) scans. * Muscle metabolism/ exercise tests * Taste strips * Muscle and/or skin biopsies/ red light therapy * Retinal imaging/ eye tracking * Sleep study * ODD visits also include: * Cytapheresis * Bone marrow aspirate * EVEN visits also include: * Hyperglycemic CLAMP * Lumbar Puncture (LP) * Continuous Glucose Monitor (CGM)