Freethought & Rationalism Archive

John Page · 04-30-2003, 11:50 AM

Anyone care to venture an opinion, see article below. I'm thinking that even if we can determine the neuro-biological preconditions for pain, actually *experiencing pain* requires a "consciousness infrastructure".

Quote:

Fish do feel pain, scientists say

The first conclusive evidence of pain perception in fish is said to have been found by UK scientists.

Fish have pain receptors like us. This complements earlier findings that both birds and mammals can feel pain, and challenges assertions that fish are impervious to it.

The scientists found sites in the heads of rainbow trout that responded to damaging stimuli.

They also found the fish showed marked reactions when exposed to harmful substances.

The argument over whether fish feel pain has long been a subject of dispute between anglers and animal rights activists.

The research, by a team from the Roslin Institute and the University of Edinburgh, is published in Proceedings B of the Royal Society, the UK's national academy of science.

The researchers, led by Dr Lynne Sneddon, say the "profound behavioural and physiological changes" shown by the trout after exposure to noxious substances are comparable to those seen in higher mammals.

They investigated the fish for the presence of nociceptors, sites that respond to tissue-damaging stimuli.

Multiple sensitivity

The researchers applied mechanical, thermal and chemical stimuli to the heads of anaesthetised fish and recorded their neural activity.

Dr Sneddon said: "We found 58 receptors located on the face and head of the trout that responded to at least one of the stimuli. "Of these, 22 could be classified as nociceptors in that they responded to mechanical pressure and were stimulated when heated above 40 Celsius. Eighteen receptors also responded to chemical stimulation and can be defined as polymodal nociceptors."

These polymodal receptors are the first to be found in fish, and resemble those in amphibians, birds and mammals, including humans. But mechanical thresholds were lower than those found in human skin, for example, perhaps because fish skin is relatively easily damaged.

The mere presence of nociception in an animal is not enough to prove that it feels pain, because its reaction may be a reflex. Proof requires demonstrating that the animal's behaviour is adversely affected by a potentially painful experience, and that these behavioural changes are not simple reflex responses.

Hurt trout behaved differently
So the researchers injected bee venom or acetic acid into the lips of some of the trout, with control groups receiving saline solution injections or simply being handled. All the fish had been conditioned to feed at a ring in their tank, where they were collected for handling or injection. Dr Sneddon said: "Anomalous behaviours were exhibited by trout subjected to bee venom and acetic acid. Fish demonstrated a 'rocking' motion, strikingly similar to the kind of motion seen in stressed higher vertebrates like mammals. The trout injected with the acid were also observed to rub their lips onto the gravel in their tank and on the tank walls. These do not appear to be reflex responses."

The fish injected with venom and acid also took almost three times longer to resume feeding than the control groups. Dr Sneddon said the team's work "fulfils the criteria for animal pain". Previous work on fish had looked at the elasmobranchs, fish including sharks, skates and rays with cartilaginous skeletons, and at primitive vertebrates like the lamprey.

Dr Sneddon said: "These studies did not conclusively show the presence of nociceptors. We believe our study is the first work with fish of the teleost family [those with bony skeletons], and the results may represent an evolutionary divergence between the teleost and elasmobranch lineages."

Dr Bruno Broughton, a fish biologist and NAA adviser, said: "I doubt that it will come as much of a shock to anglers to learn that fish have an elaborate system of sensory cells around their mouths... However, it is an entirely different matter to draw conclusions about the ability of fish to feel pain, a psychological experience for which they literally do not have the brains," he said." He quoted from a study by Professor James Rose of the University of Wyoming, US, in which it was found fish did not possess the necessary and specific regions of the brain, the neocortex. "Fish just don't have the brains to recognise pain"

pz · 04-30-2003, 12:38 PM

Ack. What can I say?

I happen to be a developmental neurobiologist who studies, among other things, the assembly of the cutaneous sensory array in embryonic and larval zebrafish. I'd really be interested to discover that there is someone here more qualified than I am to address this specific question.

The answer is: it's a stupid question. Of course they're conscious. My fish build a very elaborate network of sensory fibers 16 hours after the egg is fertilized. These fibers feed into a complex spinal circuit with output to the hindbrain and midbrain, and recieve significant vestibular and hindbrain input, within a few hours of that. By 22 hours, they respond to noxious stimuli with an increase in somatic motor output (a fancy way of saying they thrash in pain).

This is in an embryo. By the time they reach the early larval stages, a few days, I throw up my hands and give up because the interconnections get too complicated.

Given that "consciousness" is a fuzzy and hard-to-tackle term, I'd still have to say that all the anatomical and behavioral correlates are present in fish. If you say they aren't, you're going to have to say that babies aren't conscious, either. They sense the world around them and they react to it, and further, they generate responses to purely internal neural activity.

That said, though, I also have to say that I don't think consciousness is that big a deal. Ants are conscious, too.

Clutch · 04-30-2003, 12:52 PM

What is it about the UK? Cripes, I was living there a few years back when the press made a big deal about a paper in ethology that claimed to establish that deer become exhausted and feel anxiety when they're chased down and shot.

The anti-hunt lobby got up in arms, the papers and the Beeb went crazy over it.

Well, what the fuck did they think beforehand? That deer had oatmeal in their heads? That they collapsed in a heap after the hounds ran them, as a show of energy?

Are fish conscious? Of course. Are fish self-conscious? Almost certainly not.

pz · 04-30-2003, 01:07 PM

Quote:

Originally posted by Clutch
Are fish self-conscious? Almost certainly not.

Mine sure aren't. They have no sense of shame at all, flaunting their sleek, naked bodies in tantalizing gyrations, indulging in exuberant public sex acts with everyone in their school every morning. It's an orgy all the time in there, I tell you.

Clutch · 04-30-2003, 01:09 PM

Wow. Is there room for you in the tank?

pz · 04-30-2003, 01:16 PM

Quote:

Originally posted by Clutch
Wow. Is there room for you in the tank?

No, dang it. They're all in these little 5g tanks.

I'll admit that sometimes I think my wife would look really hot in a silver one piece bathing suit with blue-black stripes, though. Especially if she could learn to do that little flank shimmy and dart that courting zebrafish do.

Infinity Lover · 04-30-2003, 01:31 PM

I'd say yes; fish are concious (same as anything with a brain is). But their level of conciousness is significantly lower than ours.

For instance: how could they ever swim in groups (of their own specific kind to boot), unless their fishy brains can somehow distinguish between being in that group and not being in it?

Clutch · 04-30-2003, 01:58 PM

Quote:

flank shimmy

Now that is definitely going to become a euphemism!

Heya, hon? Let's get outta here, and you can show me a bit of that flank shimmy!

John Page · 04-30-2003, 02:13 PM

Quote:

Originally posted by Clutch
Now that is definitely going to become a euphemism!

Heya, hon? Let's get outta here, and you can show me a bit of that flank shimmy! [/B]

Quote:

Put thy shimmy on, Lady Chatterley!
Lawrence D. H. 1885 1930 British novelist. Lady Chatterley's Lover, Ch. 15

Pyrrho · 04-30-2003, 06:25 PM

This discussion reminds me of what Hume had to say about reason in animals in An Enquiry Concerning Human Understanding. You can click on SECTION IX. Of the REASON of ANIMALS. to get directly to the relevant section, and within the text, you can click on the symbol for the footnote to take you to the footnote, and from the footnote, if you click on the symbol for the footnote, it will take you back to the main text.

Whenever I meet a person, I do not dissect him or her in order to decide whether or not he or she feels pain. The same approach works with all kinds of animals.

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04-30-2003, 12:38 PM	#2
pz Veteran Member Join Date: Aug 2001 Location: Morris, MN Posts: 3,341	Ack. What can I say? I happen to be a developmental neurobiologist who studies, among other things, the assembly of the cutaneous sensory array in embryonic and larval zebrafish. I'd really be interested to discover that there is someone here more qualified than I am to address this specific question. The answer is: it's a stupid question. Of course they're conscious. My fish build a very elaborate network of sensory fibers 16 hours after the egg is fertilized. These fibers feed into a complex spinal circuit with output to the hindbrain and midbrain, and recieve significant vestibular and hindbrain input, within a few hours of that. By 22 hours, they respond to noxious stimuli with an increase in somatic motor output (a fancy way of saying they thrash in pain). This is in an embryo. By the time they reach the early larval stages, a few days, I throw up my hands and give up because the interconnections get too complicated. Given that "consciousness" is a fuzzy and hard-to-tackle term, I'd still have to say that all the anatomical and behavioral correlates are present in fish. If you say they aren't, you're going to have to say that babies aren't conscious, either. They sense the world around them and they react to it, and further, they generate responses to purely internal neural activity. That said, though, I also have to say that I don't think consciousness is that big a deal. Ants are conscious, too.

04-30-2003, 12:52 PM	#3
Clutch Veteran Member Join Date: Oct 2001 Location: Canada Posts: 3,751	What is it about the UK? Cripes, I was living there a few years back when the press made a big deal about a paper in ethology that claimed to establish that deer become exhausted and feel anxiety when they're chased down and shot. The anti-hunt lobby got up in arms, the papers and the Beeb went crazy over it. Well, what the fuck did they think beforehand? That deer had oatmeal in their heads? That they collapsed in a heap after the hounds ran them, as a show of energy? Are fish conscious? Of course. Are fish self-conscious? Almost certainly not.

04-30-2003, 01:09 PM	#5
Clutch Veteran Member Join Date: Oct 2001 Location: Canada Posts: 3,751	Wow. Is there room for you in the tank?

04-30-2003, 01:31 PM	#7
Infinity Lover Veteran Member Join Date: Jan 2002 Location: The Netherlands Posts: 1,047	I'd say yes; fish are concious (same as anything with a brain is). But their level of conciousness is significantly lower than ours. For instance: how could they ever swim in groups (of their own specific kind to boot), unless their fishy brains can somehow distinguish between being in that group and not being in it?

04-30-2003, 06:25 PM	#10
Pyrrho Veteran Member Join Date: Mar 2003 Location: United States Posts: 7,351	This discussion reminds me of what Hume had to say about reason in animals in An Enquiry Concerning Human Understanding. You can click on SECTION IX. Of the REASON of ANIMALS. to get directly to the relevant section, and within the text, you can click on the symbol for the footnote to take you to the footnote, and from the footnote, if you click on the symbol for the footnote, it will take you back to the main text. Whenever I meet a person, I do not dissect him or her in order to decide whether or not he or she feels pain. The same approach works with all kinds of animals.

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