Their research is flawed and i wish i could of got this artical for Wayne eariler I got this from Dr Bruno Broughton today :
A rebuttal to the paper: ?Do fish have nociceptors: Evidence for the evolution of a vertebrate sensory system? published in Proceedings of the Royal Society, 2003 by Sneddon, Braithwaite and Gentle.
By Prof. James D. Rose
The paper by Sneddon, et al. is seriously flawed and does not provide any legitimate evidence that trout are capable of feeling pain.
The crux of the matter is that the authors of this paper used an invalid way of attempting to identify pain. Thus, this paper does not actually deal with pain (conscious experience). It deals only with nociception (unconscious responses to noxious stimuli). I have already addressed the kinds of conceptual confusions that undermine the paper by Sneddon et al. in my 2002 Reviews in Fisheries Science Paper. They did not cite this paper and apparently hadn't read it.
The flaws in their argument include the following:-
(1) Their definitions of pain and nociception are invalid and misleading. Pain, as defined by investigators who study it (e.g. the International Association for the Study of Pain) is purely a conscious experience, with a sensory and emotional component. The detection, processing and transmission of information related to injury by lower levels of the nervous system (below the neocortex of the cerebral hemispheres) is unconscious nociception and not pain. Contrary to the assertions of Sneddon, et al. complex, non-reflexive behaviors can be purely nociceptive (and unconscious) as well.
For example, humans with extensive damage or dysfunction of the neocortex in the cerebral hemispheres can still make a complex of responses including facial displays, vocalizations, and struggling and avoidance reactions to nociceptive stimuli, but they are unconscious and unable to experience pain. By the definition of pain used by Sneddon et al. it would be concluded that these unconscious humans are feeling pain rather than making purely nociceptive responses, which is clearly erroneous.
There are many other examples of complex, non-reflexive behaviors that can be performed unconsciously, like the fact that sleepwalkers can open doors, navigate around obstacles and speak while unconscious during deep sleep.
(2) Secondly, a sustained change in behavioral activity in response to a sustained nociceptive stimulus (in the Sneddon, et al. paper, the bee venom or acid injection in the jaw), shows nothing more than that behavior can be persistently changed, especially if a nociceptive stimulus is sustained; there is nothing about these behavioral responses, including the rocking behaviors and jaw rubbing by the fish that proves conscious awareness. Furthermore, it is likely that a sustained nociceptive stimulus would cause a hormonal stress response that could, by itself, produced a sustained change in behavior, purely unconsciously.
Most important, in order to show that a fish (or any organism) experiences pain, it is necessary to show that a fish has consciousness. Without consciousness, there is no pain. Nothing in the information presented in this paper necessitates predication of consciousness for its explanation and the authors don't even deal with this essential issue.
Furthermore, as I have shown in my 2002 Reviews in Fisheries Science paper there is extensive scientific evidence which shows that pain and consciousness depend on very specific brain regions, namely specialized neocortical regions of the cerebral hemispheres. These brain regions are absent in fishes and there are no likely alternative systems to perform the same tasks. Consequently, there is no basis for assuming that a fish might have a capacity for consciousness or pain.
theres more below!