RecruitingBrain Connectivity Changes With Spinal Cord Stimulation and Treatment of Chronic Pain: A Resting State NIRS/EEG StudyThis study aims to assess how use of spinal cord stimulation for the treatment of chronic pain impacts brain structure and function. The investigators will use a non-invasive neuroimaging technique called resting state Near Infrared Spectroscopy and Electroencephalography (rs-fNIRS/EEG). The investigators will enroll Veterans who are currently receiving care at the Medical Center and who are either long term users of SCS for the treatment of their chronic pain or being evaluated for use of SCS to treat their pain.