Functional and structural imaging of pain-induced neuroplasticity.

PURPOSE OF REVIEW: The understanding of the mechanisms underlying chronic pain is of major scientific and clinical interest. This review focuses on neuroimaging studies of pain-induced neuroplastic changes in the human brain and discusses five major categories of pain-induced neuroplastic changes. RECENT
FINDINGS: First, peripheral or central sensitization may result in increased nociceptive input to the brain and also changes the processing of nociceptive information within the brain. Second, chronic nociceptive input from the periphery or from lesions within the central nervous system may result in cortical reorganization and maladaptive neuroplasticity within somatosensory and motor systems. Thirdly, there is evidence for pain-induced changes in large-scale neuronal network connectivity. Fourth, in patients with chronic pain, structural brain changes may occur. Finally, there is discussion that in chronic pain patients the endogenous pain-modulatory system may function aberrantly.
SUMMARY: Recent work has substantially broadened our insights into neuroplastic changes that are involved in pain chronification. Future research will focus on the question of whether neuroimaging techniques can be used in the individual chronic pain patient as a biomarker that would allow for an objective diagnosis of different pain conditions and for the prediction of individual responses to specific therapies.