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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).
The point of the experiment was not to prove the type of fish.
[..] 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.
"It's OK to eat the barrel of a gun cause then you don't have any feelings."
-- K. Cobain
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
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)
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.
* Dave Lister: Sometimes I think it's cruel giving machines a personality. My mate Petersen once brought a pair of shoes with artificial intelligence. Smart Shoes, they were called. It was a neat idea. No matter how blind drunk you were, they would always get you home. Then he got ratted one night in Oslo, and woke up the next morning in Burma. See, the shoes got bored just going from his local to the flat. They wanted to see the world, man, y'know? He had a helluva job getting rid of them. No matter who he sold them to, they'd show up again the next day! He tried to shut them out, but they just kicked the door down, y'know?
* Arnold Rimmer: Is this true?
* Dave Lister: Yeah! Last thing he heard, they'd sort of, erm, robbed a car and drove it into a canal. They couldn't steer, y'see.
* Arnold Rimmer: Really?!
* Dave Lister: Yeah. Petersen was really, really blown away by it. He went to see a priest. The priest told him, he said, it was alright, and all that, and the shoes were happy, and they'd gone to heaven. Y'see, it turns out shoes have soles.
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.
No. We don't. That's the whole point. Dark matter wasn't invented for the hell of it. Astronomers resisted it for decades. It was ultimately accepted precisely because it continued to pass observational tests and other theories didn't.
It's possible to cook up alternative theories to explain individual phenomena such as galactic rotation curves (e.g., MOND). But they all fail when you try to simultaneously explain multiple phenomena such as galactic rotation curves and CMBR anisotropies and early universe structure formation and galaxy cluster dynamics and ... you get the idea.