Bingel U, Schoell E, Büchel C. Imaging pain modulation in health and disease. Curr Opin Neurol. 2007 Aug;20(4):424-31.

PURPOSE OF REVIEW: In this review, we discuss recent advances in pain imaging research. We focus on the involvement of endogenous pain control mechanisms in the healthy central nervous system and the potential contribution of failure within this system for chronic pain states. RECENT FINDINGS: Nociceptive information processing and related pain perception is subject to substantial pro and antinociceptive modulation. Recent studies demonstrate that this modulation can take place at any stage of ascending information processing. A network of cortical, predominantly mesial and frontal areas, in combination with specific brainstem nuclei, appear to be the key players in the context of endogenous pain modulation. Recent findings from functional and anatomical neuroimaging support the notion that an altered interaction of pro and antinociceptive mechanisms may contribute to the development or maintenance of chronic pain states. The additional use of pharmacological intervention in pain imaging research provides an alternative tool for investigating mechanisms of pain modulation. SUMMARY: Top-down pain modulation relies on both cortical and subcortical structures. Research on the involved circuitry, including the implemented mechanisms, is a major focus of contemporary neuroscientific research in the field of pain and will provide new insights into the prevention and treatment of chronic pain states.