State vs. Trait Alterations in Low Back Pain

On a day in which participants don't have any pain or a pain ranging from 0-2 (on a numerical rating scale of 0-10), they will undergo all the study measures (see primary outcome measures for detail): clinical exam, QST, SSRs, CPM, rsMRI, lumbar MRI, MRS, and blood sample.

On a day in which patients have an ongoing typical low back pain episode of an intensity of 3 or more (on a numerical rating scale of 0-10), they will undergo all the study measures (see primary outcome measures for detail), except the lumbar MRI: clinical exam, QST, SSRs, CPM, rsMRI, MRS, and blood sample.

On a day in which participants don't have any pain or a pain ranging from 0-2 (on a numerical rating scale of 0-10), an experimental pain state will be induced using a high concentration (8%) Qutenza patch, containing capsaicin. All the study measures will be performed (see primary outcome measures for detail), except the lumbar MRI and blood sample: clinical exam, QST, SSRs, CPM, rsMRI, MRS.