Time frame: Baseline and 3 fMRI sessions (Visit 1, 2, 9, and 16). Active enrollment provides up to 8 weeks to complete all study interventions, scans, and assessments.
Changes in visual analog scale (VAS) pain ratings will be assessed in response to the straight leg raise test and lying supine in the MRI scanner.
Psychophysical Assessment of Pain: As previously in all of our previous pain studies, pain intensity and unpleasantness ratings will be assessed with a Visual Analog Scale. These scales 1) provide reliably separate assessment of experimental and clinical pain intensity and unpleasantness, 2) are internally consistent, and 3) approximate ratio scale measurement accuracy. The minimum rating ("0") is designated as "no pain" whereas the maximum ("10") is labeled as "most intense imaginable" or "most unpleasant imaginable".
Higher numbers correspond to higher perceived pain