The investigators tested whether pain decrease can be observed centrally with non-invasive
brain imaging in CBP subjects receiving Lidoderm. The investigators first tested effects of
5% Lidoderm patched in an open labelled trial. Next the investigators compared the effects of
Lidocaine versus Placebo patches. Three time points were evaluated: baseline (before
treatment) and 6 hours and 2 weeks after treatment. The latter trial was a 2 arm, double
blind, placebo controlled trial, where participants either received Lidoderm or placebo
patches, without cross over.