Pain or Illness

Pain, especially in its acute form, is usually a reflection of a tissue-damaging or potentially tissue-damaging stimulus. There is a transmission system that conveys this information to the central nervous system. This phenomenon is called nociception. Pain is more complex than other sensory systems such as vision or hearing because it not only involves the transfer of sensory information to the nervous system, but produces suffering which then leads to aversive corrective behavior. In certain disease states, defects in the transmission system can of themselves generate false information to the nervous system, as though tissue damage were occurring in the periphery. An example of this is phantom limb pain, in which the individual often has a crushing type of pain in a foot that has been amputated.