Pain, Neurophysiological Mechanisms of

  • Patrick D. Wall
Part of the Readings from the Encyclopedia of Neuroscience book series (REN)


Pain was classically defined as the sensation evoked by injury. This attractively simple definition neglects the observed phenomena of behavior and physiology and was replaced by the International Association for the Study of Pain in 1979 with the following definition and with a crucial coda:
  • Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Pain is always subjective. Each individual learns the application of the word through experience related to injury in early life. It is unquestionably a sensation in a part of the body but it is also always unpleasant and therefore also an emotional experience.

  • Many people report pain in the absence of tissue damage or any likely pathophysiological cause, usually this happens for psychological reasons. There is no way to distinguish their experience from that due to tissue damage, if we take the subjective report. If they regard their experience as pain and if they report it in the same ways as pain caused by tissue damage, it should be accepted as pain. This definition avoids tying pain to the stimulus. Activity induced in the nociceptor and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state, even though we may well appreciate that pain most often has a proximate physical cause.


Dorsal Horn Herpes Zoster Noxious Stimulus Transcutaneous Electrical Nerve Stimulation Neurophysiological Mechanism 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Further reading

  1. McMahon SB, Wall PD (1985): Microneuronography and its relation to perceived sensation: A critical review. Pain 21: 209–229CrossRefGoogle Scholar
  2. Melzack R, Wall PD (1982): The Challenge of Pain. New York: Basic BooksGoogle Scholar
  3. Wall PD (1984): Introduction. In: The Textbook of Pain, pp 1–16, Wall PD, Melzack R, eds. Edinburgh: Churchill LivingstoneGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1988

Authors and Affiliations

  • Patrick D. Wall

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