Abstract
Individual differences in pain sensitivity have long remained a perplexing and challenging clinical problem. How can one individual have a sensory experience that is vastly different than that of another, even when they have received similar sensory input? Developing an understanding of such differences and the mechanisms that support them has progressed substantially as psychophysical findings are integrated with measures of brain activation provided by functional brain imaging techniques. Continued delineation of these mechanisms will contribute substantially to the development of combined psychophysical/psychological models that can be used to optimize pain treatment on an individual-by-individual basis.