Demographics for Subjects.

Sex: F = Female; M = Male. Hand: L = Left; R = Right; a = Ambidextrous. Ethnicity: C = Caucasian; B = Black African American. Pain Thresh Level = Pain Threshold Level of electrical stimulation used in fMRI; Meds = Medication; Vit Sup = Vitamin Supplements. *Denotes the two individuals misclassified by the Sparse Logistic Regression decoder. All Chronic Pain subjects were diagnosed with muscle-skeletal lower back chronic pain.