LAUSR

The usefulness of visceral pain is not immediately apparent. herrington defined pain as the psychical adjunct of a protective eflex, implying that pain has a protective and useful role. But what s the usefulness of the pain of childbirth, of a bladder infection, f a renal colic or even of a simple gastroenteritis? Many of these vents are related to normal functions of the body and some – like hildbirth – are intrinsic to the perpetuation of our species, which houldbe themost powerful drive of evolution.Humanbeingshave uzzled about the meaning of visceral pain since the beginning of ime: In pain thou shalt bring forth children, says the Bible: so, at east for the pain of childbirth, it must be God’s curse to women for heir sins. The more we know about the mechanisms of visceral pain the ore we find important differences in the neurobiological proesses that mediate this form of pain when compared to those esponsible for somatic pain [1]. Some internal organs do not ave sensors capable of generating conscious perceptions. Afferent ignals from viscera such as the liver, the spleen or the kideys never reach consciousness, rendering these organs incapable f producing pain. Visceral nociceptors innervating other organs ncludemany that encode the full rangeof stimulus intensities from nnocuous to noxious and are probably responsible for the transiion of the sensation of distension in the bladder and rectum from ullness to pain. Visceral pain is the most common form of pain in the clinic, xperienced by all of us and often inadequately treated as just a ymptom of an underlying disease. We need to know more about hemechanisms of visceral pain and it is important thatwedevelop ays of studying how the brain processes the signals from our nternal organs that eventually produce pain. One novel method is o literally look at the pain, identifying which regions of the brain re more active while we feel visceral pain and how the activity in hese brain areas is modulated over time in parallel with changes n the intensity and quality of the painful sensations. This issue of he Scandinavian Journal of Pain includes a comprehensive review f the techniques for imaging visceral pain [2], the very procedures hat allow us to probe the basic mechanisms underlying visceral ain in conscious humans. This is especially important for vis-