In this protocol, "Brain imaging biomarkers for response to Spinal Cord Stimulation in patients with chronic low back pain," the investigators plan to perform brain mapping studies in 42 patients who are undergoing spinal cord stimulation (SCS) for chronic low back pain (CLBP) as part of the participants normal clinical care during a 2-year period. This imagining study is completed for research purposes. There is no standard of care imaging for the participants. This study requires two visits in total. During the baseline visit, participants will undergo imaging acquisition protocol and corresponding assessments. Participants will have another follow-up visit (potentially remotely) for final assessments two weeks after the SCS treatment. The objective of the study is to investigate potential imaging biomarkers that can predict response to the SCS treatment. Specifically, the investigators hypothesize that the connectivity of a certain region of the brain (specifically the subgenual cingulate) prior to SCS may serve as a possible pre-operative imaging-based biomarker on response to SCS. The findings of the study may further enhance investigators understanding of the connectivity between brain areas that are critical to the therapeutic response to SCS in CLBP patients and that can be used as a putative biomarker to select patients who may respond to SCS.