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Dead Salmon's "Brain Activity" Cautions fMRI Researchers
AthanasiusKircher sends in a Wired writeup on what should surely be a contender in the next Improbable Research competition: wiring a dead salmon into an fMRI machine and showing it pictures of humans designed to evoke various emotions. "When they got around to analyzing the voxel... data, the voxels representing the area where the salmon's tiny brain sat showed evidence of activity. In the fMRI scan, it looked like the dead salmon was actually thinking about the pictures it had been shown. ... The result is completely nuts — but that's actually exactly the point. [Neuroscientist Craig] Bennett... and his adviser, George Wolford, wrote up the work as a warning about the dangers of false positives in fMRI data. They wanted to call attention to ways the field could improve its statistical methods. ... Bennett notes: 'We could set our threshold [of significance] so high that we have no false positives, but we have no legitimate results.... We could also set it so low that we end up getting voxels in the fish's brain. It's the fine line that we walk.'" The research has been turned down by several publications, according to Wired, but a poster is available (PDF).
Wiring red herring's brain? Will it think too?
And here I though I had exterminated the last of the zombie salmon.
The point of the experiment was not to prove the type of fish.
Fish are capable of all sorts of feelings for humans.
WARNING!!! Pun approaching!!
[..] it looked like the dead salmon was actually thinking about the pictures it had been shown. ... The result is completely nuts -- [...] as a warning about the dangers of false positives [...]
Looks to me like the dark matter syndrome: "Our theories wrong? Our calculations off by an insane amount? Unpossible! That can never be. Nature must be lying!"
Has anyone even checked if a dead brain can still have flows of energy through its brain? I mean light patterns still reach the retinas, and can still trigger signals, depending on the state of the neurons there. How long was that salmon dead? I know that pigs can be frozen to be clinically dead for long times (90+ minutes), and still be revived without much damage.
I'd at least check if there are actual signals of current going trough the brain (with an OTHER (better) instrument, before dismissing it. Every unchecked assumption is a good chance for flaw in your study. You wouldn't want it to be dismissed by peer review, because of a faulty assumption.
Any sufficiently advanced intelligence is indistinguishable from stupidity.
God bless you, Terri Schiavo.
Not sure if this was a troll but I'll bite.
This is not about brain activity post-mortem! This is about the stupidity of some fMRI data. This is about the voodoo correlations that come out of fMRI data in popular research that is peer reviewed. They did this to prove a point, not claim dead fish think. Even if we did, I could use your logic to claim that every time we bury a dead person we are burying them with cognitive abilities -- obviously not true! I thought the summary covered that very well as the paper being titled "Neural correlates of interspecies perspective taking in the post-mortem Atlantic Salmon: An argument for multiple comparisons correction."
My work here is dung.
No no he's not dead, he's, he's restin'! Remarkable fish, the salmon, idn'it, ay? Beautiful plumage!
It was probably a salmon of doubt.
The Tao of math: The numbers you can count are not the real numbers.
Even vegetables put into an MRI machine for a functional scan can show some 'brain activity', simply because the fMRI doesn't actually show 'brain activity', it (in its typical configuration) shows blood oxygenation concentration levels in various places in the brain. The real problem is translating increasing or decreasing levels of oxygenation into brain activity. That's precisely what this study is showing: even a dead fish has changing brain-blood oxygenation levels. You need to remember to do the science and the math part of the problem, and make sure that the statistics are really showing meaningful relations.
The question remains as to what functionality is required to call a person "alive" or "brain dead". If you want to be as absolutely conservative as possible, anyone with a beating heart and working brain stem (corneal reflexes, heart-beat signal, breathing stimuli, etc) and can be considered alive, even if their entire frontal lobe has been entirely caved in removing any wisp of humanity and they aren't even capable of controlling their bowels or bladder or many other autonomic or homeostatic functions. Whether you think it's cruel to pull the plug on someone in this state is entirely up to personal beliefs and/or religious convictions. Medicine tries not to tread too deeply into this water, simply because it's not worth it to rehash the ethical dilemmas with no new science to change anyone's opinion. We leave it up to the individuals (through advanced directives, living wills, etc) and their families to choose.
Just don't be fooled into thinking that scattered activity in a bundle of nerves we happen to call a brain necessarily means she's "alive".
"Victory means exit strategy, and it's important for the President to explain to us what the exit strategy is." G.W.Bush
And yet once again, you live up to your username! Bravo Dude! Bravo!
When information is power, privacy is freedom.
"It's OK to eat the barrel of a gun cause then you don't have any feelings."
-- K. Cobain
I for one welcome our new zombie salmon psychotherapist overlords.
I can't believe I'm going to say this, but:
Fixed that for you.
Oh, was that my outside voice?
Atlantic salmon is called Salmo salar in biology-speak. It is the model species of the entire order Salmoniformes. Salmon doesn't get any truer than that. Pacific species belong to the genus Oncorhynchus. They are true salmons too. "Trouts" belong to both Oncorhynchus and Salmo (and another 5 genera). Some of these trouts have anadromous forms (that is, go to the seas and return to the rivers to spawn), for instance, the rainbow trout (called steelhead in its anadromous form) is Oncorhynchus mykiss and the brown trout (sea trout) is Salmo trutta.
I thought igNobel prizes were for genuinely useless research. This research is very useful for highlighting some of the problems with fMRI research.
Insanity: voting in the same two parties over and over again and expecting different results
wrong
The mechanisms are the most important thing. What is fMRI actually measuring? It doesn't measure activity directly, since it's not built into the brain. Ergo, it measures activity indirectly by measuring something else entirely. But anything which also generates that something else will also be detected.
This is less a false positive than it is a complete confusion between direct and indirect observations. The falseness is not in the measurement but in the observer.
Sir Arthur Conan Doyle would have loved this finding, as he often has his most famous creation of Sherlock Holmes make snide remarks about the folly of poor observation and the absurdities that follow.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
you insensitive cod!
But this study showed that dead salmon can show just as much brain activity as Terri Schaivo...This study just shows that a "dead" organism with a brain that hasn't yet decomposed can still support some processes.
Bzzzt. Wrong. The entire point the write up was to warn about the danger of false positives. Your attributing of brain activity to random, natural noise is exactly the danger they want to avoid.
Dark matter and dark energy aren't just theories that a bunch of arrogant pricks pulled out of their asses.
Ummm, actually...
We have absolutely no direct evidence of either.
We have numerous alternative theories that explain, without resorting to saying the universe consists of 96% invisible voodoo, various anomalies such as gravitational rotation and the implied anisotropy of the CMB.
Keep in mind that until last week, we had no direct evidence of something so basic to modern physics as the Bohr model; before that, we had "hooked" atoms dating back to (at least) Epicurus. Theories come and go, and without reproducible, experimental evidence, we have at best a model that fits the data - NOT, as far too many people seem to believe, a necessarily accurate description of objective reality.
I find it amazing that people who haven't even bothered to study the data or the reason for hypotheses like dark matter feel the need to make ass backwards comments about people who've literally dedicated their lives to it.
The GP said no such thing. He merely hypothesized, and not without some basis in fact, that a dead fish may well still have neural activity. Keep in mind, for several hours after death-of-the-whole (depending on the cause, of course), the vast majority of cells in the body still work just fine.
Now, if he had said something like "how do we know gravel doesn't have neural impulses", I would agree with your position; but we so poorly understand "death" that your ridicule reflects worse on you than on your target.
Hey guys - I am the first author of the Salmon poster. If you have any questions that you would like us to answer then post it as a reply below and I will do my best to respond as soon as I can.
You can find some more information on the poster at the following link:
http://prefrontal.org/blog/2009/06/atlantic-salmon-index/
Best ~ Craig Bennett
No sir. What it proves is the existence of the sole.
Yeah, the measurements were right off the scales.
Crumb's Corollary: Never bring a knife to a bun fight.
AC - The paper has been rejected once so far. I won't mention the journal, but it was rejected on an editorial basis before it reached the peer review stage. I can only conjecture regarding why the editor decided to pass on the paper, but it was not (to my knowledge) rejected for any methodological deficiencies. We are currently in the review stage at a second journal and the reviewers had no trouble with our methods, only how we argue for multiple comparisons correction without stepping on too many toes.
As an interesting aside, the poster was also rejected at first. All the peer reviewers thought is was a joke and voted to exclude it from the conference. Once it went before the program committee they realized that, even though we had an odd approach, the conclusions of our data were sound and that we had a very good point to make.