Modulation of Motor Function by Stimulation of the Central and Peripheral Nervous System

Objectives When a stroke damages the part of the brain that controls movement, people have weakness and difficulty using their hand. There is often some improvement, but many people have permanent disability in using the affected hand. Our previous research has shown that if we stimulate the nerves or the brain, we can temporarily improve how fast people with and without strokes can move their hands. But improvement is very slight and doesn t last long. In this study, we are trying to see if different combinations of brain, skin and nerve stimulation might cause more improvement in motor function or learning. For this study, we will only include healthy people who have not had a stroke. We will use one or more types of electrical and magnetic stimulation of skin, nerves and the brain, or recording of behavior or brain activity alone without stimulation. Study Population Up to 1500 healthy volunteers, age 18 and older. What will volunteers do in this study Visits may include the following procedures: Electromyography (EMG) which measures electrical activity of muscles. Transcranial Magnetic Stimulation (TMS) where a wire coil is placed on the scalp, and brief electrical current creates a magnetic pulse that temporarily affect brain activity. This may feel like a pulling sensation where the coil is placed, and may result in twitches in the face, arm, or leg. Transcranial direct current stimulation (tDCS), a technique in which a very weak electrical current is applied to the head in order to stimulate the brain. Nerve Stimulation, where sticky pads or small metal disk electrodes attached to wires onto the skin to record muscle and nerve activity. Magnetic resonance imaging (MRI) which uses a strong magnetic field and radio waves to take pictures of the brain. Some MRIs the volunteers are asked to lie still, and in others are asked to do various movements. Magnetic resonance spectroscopy (MRS) uses a strong magnetic field and radio waves to take pictures of various chemicals in the brain using an MRI scanner. Electroencephalogram (EEG) to record the electrical activity of the brain ( brain waves ). Magnetoencephalography (MEG) records small magnetic field changes from brain activity. Eye movement recordings Behavioral Tests Questionnaires Pregnancy test (for those capable of getting pregnant) How long is the study? Volunteers in this study may have multiple visits. Each visit may last up to 8 hours. The number of visits we depend on the data the researchers want to collect. You may be asked to come back for visits over multiple years (up to 20 years). Taking part in this study is completely voluntary. People who volunteer to be in the study can change their mind at anytime.

* INCLUSION CRITERIA: 1. Age 18 and older 2. Willingness and ability to give consent 3. Normal neurological examination 4. Clearly dominant handedness (right or left) as assessed by Handedness scales EXCLUSION CRITERIA: 1. Any severe or progressive neurological disorder or severe medical condition, or history of seizures 2. Chronic use of medications acting primarily on the central nervous system, which lower the seizure threshold or significantly alter cortical excitability such as antipsychotic drugs (chlorpromazine, clozapine), tricyclic or other antidepressants, or prescription stimulants. 3. Pacemakers or other implanted electrical devices, brain stimulators, some types of dental implants, aneurysm clips (metal clips on the wall of a large artery), metallic prostheses (including metal pins and rods, heart valves, and cochlear implants), permanent eyeliner, implanted delivery pump, or shrapnel fragments 4. Diagnosis of drug dependence made by a health care provider (ICD-9-CM code 304) 5. Staff from our section