Grasping Function After Spinal Cord Injury

Inclusion Criteria: Participants who are unimpaired healthy controls: * Male and females between ages 18-85 years * Right handed * Able to complete precision grips with both hands * Able to complete full wrist flexion-extension bilaterally Participants who have had a spinal cord injury: * Male and females between ages 18-85 years * Chronic SCI (\> 1 year post injury) * Spinal Cord injury at C8 or above * Intact or impaired but not absent innervations in dermatomes C6. C7 and C8 during light touch and pin prick stimulus using the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) sensory scores * The ability to produce a visible precision grip force with one hand * Able to perform some small wrist flexion and extension * ASIA A,B,C, or D Exclusion Criteria: Exclusion criteria for enrollment For SCI and Healthy Control Subjects (4-8 exclusion for non-invasive brain stimulation only): * Uncontrolled medical problems including pulmonary, cardiovascular or orthopedic disease * Any debilitating disease prior to the SCI that caused exercise intolerance * Premorbid, ongoing major depression or psychosis, altered cognitive status * History of head injury or stroke * Pacemaker * Metal plate in skull * History of seizures * Receiving drugs acting primarily on the central nervous system, which lower the seizure threshold * Pregnant females * Ongoing cord compression or a syrinx in the spinal cord or who suffer from a spinal cord disease such as…