Functional imaging of pain: New insights regarding the role of the cerebral cortex in human pain perception

There has been a large increase in the use of brain imaging technologies to study pain. Most likely this trend will accelerate even more in the near future. Comparing among the studies that have examined the brain physiology of human pain perception the general impression is confusing. It seems that depending on the laboratory, the specifics of the technology used and the details of stimulus delivery, different results are obtained regarding the brain sites and their type of involvement (increased or decreased activity) in pain perception. This review is an attempt to allay some of this confusion by proposing a set of hypotheses that can explain most of the differences more coherently. The main conclusion of this review is rather surprising, because the arguments lead to the notion that the spinothalamic pathway may not be the major system involved in clinically relevant pain states.