A Novel Repetitive Synchronized Associative Stimulation Neuromodulation Approach for Spinal Cord Injury Patients

Inclusion Criteria: Male or Female subjects 1. At least 18 years old and no older than 70 years old at the time of enrollment. 2. Able-bodied subjects 3. Traumatic spinal cord injury 4. Upper limb target: neurological level at or above Thoracic 1 level, Abbreviated Injury Scale (AIS) B, C or D impairment grade, primary non-ambulatory; * Lower limb target: neurological level at or above Thoracic 10 level, with residual lower limb function; AIS B, C or D impairment grade primary could ambulate; * Trunk target: neurological at or above Thoracic 5, AIS A, B, C or D impairment grade, primary wheelchair user 5. Spinal cord injury sustained more than 6 months prior to study. 6. Movement/excitability/etc: * Upper limb target: Has detectable residual connection in upper-limb muscles in at least one side confirmed by voluntary electromyography (EMG) or detectable motor evoked potential (MEP) and a visible contraction when functional electrical stimulation (FES) is applied in the hand or wrist muscle at baseline. * Lower limb target: Has detectable residual connection in lower-limb muscles in at least one side confirmed by voluntary EMG or detectable MEP and a visible contraction when FES is applied in lower limb ankle plantar or dorsiflexor muscle at baseline. * Trunk target: Has detectable residual connection in trunk muscles in at least one side confirmed by voluntary EMG or detectable MEP and a visible contraction when FES is applied in trunk muscle at baseline. 7. Able to commit to intervention and assessment sessions over a maximum duration of 2 months. Exclusion Criteria: 1. Has traumatic brain injury, stroke, multiple sclerosis, or other disorders that could affect neuromotor function. 2. Has severe spasticity that could prevent the study protocol as determined by the investigator. 3. Has major executive dysfunction, dementia, depression, neurocognitive impairments, or other major medical co-morbidities. 4. Has contraindications for transcutaneous stimulation using FES or TSCS such as breakdown of skin in the area that will come into contact with electrodes, thrombosis, or skin disease. 5. Has a poorly managed autonomic dysreflexia that could be triggered by transcranial magnetic stimulation (TMS), FES, or TSCS. 6. Has a history of prior intracranial surgery or known medical risks that would limit TMS protocols. 7. Has a history of epilepsy, convulsion or seizures. 8. Individuals with metal implants in their head or spine near the sites to be stimulated and other implantable devices (e.g., cochlear implants) in the body that could be affected by TMS or TSCS. 9. Has implanted neurostimulator (e.g., deep brain stimulation (DBS), epidural/subdural, vagal nerve stimulation or VNS). 10. Has a cardiac pacemaker or intracardiac lines. 11. Has peripheral neuropathy, including diabetic polyneuropathy and entrapment neuropathy. 12. Has urinary tract infection, unhealed fracture, contracture, and pressure sore as determined by Braden Scale value of 14 and below. 13. Individuals who require therapy or other care that could interfere with participation in the study. 14. Individuals on investigational drugs or any other intervention known to have a potential impact on neuromotor function. 15. Individuals with substance disorders, including alcoholism and drug abuse. 16. Individuals who are pregnant, breastfeeding, or the desire to become pregnant during the study. 17. In the opinion of the investigators, the study is not safe or appropriate for the participant.