Pain and Suffering in Invertebrates?

作者：Robert W. Elwood · 发表于：ILAR Journal · 年份：2011 · DOI：10.1093/ilar.52.2.175 · 被引用次数：214 · 研究领域：Neurobiology and Insect Physiology Research、Cephalopods and Marine Biology、Insect Utilization and Effects

All animals face hazards that cause tissue damage and most have nociceptive reflex responses that protect them from such damage. However, some taxa have also evolved the capacity for pain experience, presumably to enhance long-term protection through behavior modification based on memory of the unpleasant nature of pain. In this article I review various criteria that might distinguish nociception from pain. Because nociceptors are so taxonomically widespread, simply demonstrating their presence is not sufficient. Furthermore, investigation of the central nervous system provides limited clues about the potential to experience pain. Opioids and other analgesics might indicate a central modulation of responses but often peripheral effects could explain the analgesia; thus reduction of responses by analgesics and opioids does not allow clear discrimination between nociception and pain. Physiological changes in response to noxious stimuli or the threat of a noxious stimulus might prove useful but, to date, application to invertebrates is limited. Behavior of the organism provides the greatest insights. Rapid avoidance learning and prolonged memory indicate central processing rather than simple reflex and are consistent with the experience of pain. Complex, prolonged grooming or rubbing may demonstrate an awareness of the specific site of stimulus application. Tradeoffs with other motivational systems indicate central processing, and an ability to use complex information suggests s...