Improving Motor Function After Spinal Cord Injury

The goals of this study are to examine the physiology of Central Nervous System pathways contributing to the control of upper and lower extremity movements after SCI, and to promote the recovery of extremity movements by using non-invasive brain stimulation and motor training.

This study will consist of electromyography (surface and intramuscular), peripheral nerve stimulation, and transcranial magnetic stimulation, electrical stimulation, of the hand, arm, leg, and foot representation of the primary motor cortex, as well as MRI scans of the brain. The investigators will examine the physiological measurements of upper and lower extremity muscles (such as in the first dorsal interosseous (FDI), biceps brachii (BIC), anterior deltoid (AD), tibialis anterior (TA), hamstring (HAMS) and quadriceps (QUAD)). This study may occur at the Miami Project to cure Paralysis at the University of Miami. The investigators will include subjects between the ages of 18 and 85, both healthy controls and individuals with chronic spinal cord injuries that occurred at least 6 months prior to recruitment. Both healthy controls and those with spinal cord injuries will be able to perform small hand and arm movements and small leg and foot movements. The primary outcome measures of this study are muscle responses to stimulation with magnetic pulses using TMS and electrical stimulation of a peripheral nerve in the arm or leg. The investigators propose to enhance the recovery of motor function by using new protocols of high frequency non-invasive repetitive TMS (rTMS) and motor training. Repetitive TMS will be used during hand, arm, leg and foot movements in a task-dependent manner to induce cortical plasticity and enhance voluntary output of the muscles associated with those movements. Second, rTMS will be applied in a task-dependent manner during a visuo-motor training task that also involves movements of the hands, arms, legs or feet.

Eligibility Criteria:
Inclusion Criteria:

Male and female Veterans and non Veterans with spinal cord injury at least 6 months after injury was sustained. The investigators also plan to enroll control subjects who do not have any history of spinal cord injury.

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
* Able to walk unassisted
* Able to complete full ankle flexion-extension bilaterally

Participants who have had a spinal cord injury:

* Male and females between ages 18-85 years
* Chronic SCI ( 6 months of injury)
* Spinal Cord injury at or above L5
* The ability to produce a visible precision grip force with one hand
* Individuals who have the ability to pick up a small object (large paperclip) from a table independently
* Able to perform some small wrist flexion and extension (measured by a goniometer)
* The ability to perform a small visible contraction with dorsiflexor and hip flexor muscles
* No subjects will be excluded based on their race, religion, ethnicity, gender or HIV status.

Exclusion Criteria:

Exclusion criteria for enrollment For SCI and Healthy Control Subjects (for stimulation):

* 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
* Metal plate in skull
* History of seizures
* Receiving drugs acting primarily on the central nervous system, which lower the seizure threshold (see appendix 2)
* Pregnant females
* Ongoing cord compression or a syrinx in the spinal cord or who suffer from a spinal cord disease such as spinal stenosis, spina bifida, MS, or herniated cervical disk
* Individuals with scalp shrapnel, cochlear implants, or aneurysm clips.