The neuromatrix, which is genetically determined and modified by sensory, emotional, cog- nitive, and memory experience, is the primary mechanism that generates the neural pattern that produces pain. Its output pattern is determined by multiple influences, of which the somatic sensory input is only a part, that converge on the neuromatrix. Acute pain problems evoked by brief noxious inputs have been carefully investigated by neuroscien- tists, and their sensory transmission mechanisms are generally well understood. In contrast, chronic pain syndromes that are often characterized by severe pain associated with less obvious injury or pathology involve more complex systems in the central nervous system.
