Pain testing will be conducted using a Forgioni-Barber pressure-pain stimulator to deliver 3000-gm force to the middle digit of the non-dominant middle finger for up to 120 seconds. During stimulation, subjects will press a button attached to a timer when the pressure stimulus first becomes painful (pain threshold) and will also rate their perceived pain intensity using a 0-100 numeric pain rating scale at 20 second intervals during the 2 minute exposure to the pressure stimulus. This validated protocol has been used in previous research by investigators in this study.