The objective of this project is to study the effects of an emerging noninvasive neuromodulation strategy in human stroke survivors with movement-related disability. Muscle weakness after stroke results from the abnormal interaction between cells in the brain that send commands to control movement and cells in the spinal cord that cause muscles to produce movement. The neuromodulation strategy central to this project has been shown the strengthen the physical connection between both cells, producing a change in movement potential of muscles weakened by stroke.

Stroke is a leading cause of serious long-term disability in the United States with 795,000 individuals suffering a new or recurrent stroke each year. In most cases, disability is associated with incomplete motor recovery of the paretic limb. Full recovery is often not achieved, creating a need for neuromodulation strategies that target the physiological mechanisms impaired by stroke to fully harness the adaptive capacity of the nervous system. The neuromodulation protocol that will be tested in these experiments will target connections between the brain and spinal cord with noninvasive stimulation to enhance movement potential of the hand. Individuals who experienced a single stroke at least 6 months ago may be eligible to participate.

Inclusion Criteria:

• Between the ages of 18 and 75 years old
• Diagnosis of first-ever stroke
• Stroke onset of at least six months prior to the time of participation

Exclusion Criteria:

• History of seizure or epilepsy
• Ferromagnetic metallic implants, pacemakers, other implanted devices, or ventilators (for subjects undergoing MRI)
• Pregnant or expecting to become pregnant
• Difficulty maintaining alertness and/or remaining still
• Body weight > 300 lbs due to MRI scanner dimensions (for subjects undergoing MRI)
• Cognitive or language impairments that would interfere with the ability to follow simple instructions, as judged by the investigators
• Diagnosis of movement disorder(s) other than stroke

2 years