Central nociceptive processing: networks, pain, and reorganization

Pain is the complex result of the activity of different neural structures of the brain and not simply the result of the activity of the peripheral nociceptive system. Pain results from a spatially and temporally concerted interaction of distinct modules within different brain areas. Besides the spinal cord, the most important structures are the brainstem, thalamus, primary and secondary somatosensory cortices, insula, anterior cingulate and prefrontal cortex. The central representation of pain is not rigid but may change dynamically; it may be changed by expectations, learning, coping, and chronic pain. Chronic pain is associated with changes in the peripheral and central nervous system. These changes may persist for a long time and lead to self maintenance of pain without further peripheral input.