The cortical representation of pain

Anatomical and physiological studies in animals, as well as functional imag ing studies in humans have shown that multiple cortical areas are activated by painful stimuli. The view that pain is perceived only as a result of th alamic processing has, therefore, been abandoned, and has been replaced by the question of what functions can be assigned to individual cortical areas . The following cortical areas have been shown to be involved in the proces sing of painful stimuli: primary somatosensory cortex, secondary somato sen sory cortex and its vicinity in the parietal operculum, insula, anterior ci ngulate cortex and prefrontal cortex. These areas probably process differen t aspects of pain in parallel. Previous psychophysical research has emphasi zed the importance of separating pain experience into sensory-discriminativ e and affective-motivational components. The sensory-discriminative compone nt of pain can be considered a sensory modality similar to vision or olfact ion; it becomes more and more evident that it is subserved by its own appar atus up to the cortical level. The affective-motivational component is clos e to what may be considered 'suffering from pain'; it is clearly related to aspects of emotion, arousal and the programming of behaviour. This dichoto my, however, has turned out to be too simple to explain the functional sign ificance of nociceptive cortical networks. Recent progress in imaging techn ology has, therefore, provided a new impetus to study the multiple dimensio ns of pain. (C) 1999 International Association for the Study of Pain. Publi shed by Elsevier Science B.V.