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prefrontalon 40 percent of fMRI signals do not correspond to actual brain activity

Many thanks - appreciate the kind words. Thanks also for always working to work with care in your science. It makes all the difference.

Among other challenges, when we first submitted the poster to the Human Brain Mapping conference we got kicked out of consideration because the committee thought we were trolling. One person on the review committee said we actually had a good point and brought our poster back in for consideration. The salmon poster ended up being on a highlight slide at the closing session of the conference!

prefrontalon 40 percent of fMRI signals do not correspond to actual brain activity

Yeah, it did prove to be a rather one-sided conversation... ;)

prefrontalon 40 percent of fMRI signals do not correspond to actual brain activity

Many thanks! It was a ton of fun. Hard to beleive that we are coming up on 20 years since the data for the salmon was first collected...

prefrontalon 40 percent of fMRI signals do not correspond to actual brain activity

While I would agree that the prevalence of the problem has been minimized in fMRI during the last 15 years, I disagree that our critique does not hold up. The root of our concern was that proper statistical correction(s) need to be completed in order for research results to be interpretable. I am totally biased, but I think that remains worthwhile.

prefrontalon 40 percent of fMRI signals do not correspond to actual brain activity

When we published the salmon paper, approximately 25-35% of published fMRI results used uncorrected statistics. For myself and my co-authors, this was evidence of shaky science. The reader of a research paper could not say with certainty which results were legitimate and which might be false positives.

prefrontalon 40 percent of fMRI signals do not correspond to actual brain activity

That was our paper! We showed that you can get false positives (significant brain activity in this case) if fMRI if you don't use the proper statistical corrections. We did win an Ig Nobel for that work in 2012 - it was a ton of fun.

prefrontalon 40 percent of fMRI signals do not correspond to actual brain activity

As the first author of the salmon paper, yes, this was exactly our point. fMRI can be an amazing tool, but if you are going to trust the results you need to have proper statistical corrections along the way.

prefrontalon 40 percent of fMRI signals do not correspond to actual brain activity

As the first author on the salmon paper, yes, that was exactly our point. Researchers were capitalizing on chance in many cases as they failed to do effective corrections to the multiple comparisons problem. We argued with the dead fish that they should.

prefrontalon Human neuroscience mustn't forget its human dimension

Pretty much what TeMPOraL said. You can scan pretty much anything with fMRI and find results if you don't use proper statistical corrections. I have found "significant" voxels in a pumpkin before while doing testing. Our argument was/is that scientists need to have appropriate rigor in their analyses, otherwise you can reach ridiculous conclusions - like a dead fish looking alive...

prefrontalon Human neuroscience mustn't forget its human dimension

> we have a print of the poster on our lab's wall

That's amazing - you made my day with that statement.

I left neuroscience for the software world back in 2012, so I don't have a lot of data points since then. I know between 2009 and 2012 the field went from ~50% of papers doing the right statistical corrections to about ~90%, which is a huge step in the right direction. I hope those numbers are even better today.

The expense of MRI time means that studies include far fewer subjects than they might want/need. My opinion is that there are still significant challenges that go beyond correction for multiple comparisons, like data peeking and low-power experimental designs. I think that we should move to a mindset where we need replication and convergent evidence for major claims. Not a single study with 18 college freshman participants.

prefrontalon Human neuroscience mustn't forget its human dimension

I'm the first author of the salmon fMRI paper, if you have any questions. Generally, how the investigators do their statistics can lead to implausible conclusions. Extraordinary claims should require extraordinary evidence.

prefrontalon A low-cost and shielding-free ultra-low-field brain MRI scanner

I've scanned about 300 people as part of my research career. The director of the imaging center reviewed every anatomical scan. From that group of 300 we informed about three people that they had an anomaly which should be examined by a doctor.

prefrontalon A low-cost and shielding-free ultra-low-field brain MRI scanner

Marc Abrahams, organizer of the Ig Nobels, asked us for a salmon recipe to include in a cookbook they were publishing. We sent in a single page recipe for how to cook a salmon in an MRI scanner by overriding the safety protocols. That was fun to write.

https://www.amazon.com/Ig-Nobel-Cookbook-1/dp/1939385164

prefrontalon A low-cost and shielding-free ultra-low-field brain MRI scanner

Thanks for the kind words. I am the first author of the "Neural correlates of interspecies perspective taking in the post-mortem Atlantic Salmon: An argument for multiple comparisons correction" paper. Happy to take any questions here. A link to the original poster: http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf

prefrontalon Cricut Wants Users to Pay for Unlimited Use of Cutting Machines They Already Own

My wife and I are so irritated about this. She bought a Cricut Maker last year to make masks for friends and family. Custom images were cut for every person she made a mask for. Now, nine months after we bought the machine, we will have to start paying $10/mo for the same privileges we enjoyed when we first got it.

prefrontalon Myths about how the brain works

As the first author of that paper, I approve of this link.

prefrontalon IgNobel Prize in Neuroscience: The dead salmon study (2012)

I cooked it for dinner. We kept it cold in the snow outside the building all day while we worked. Tasted like regular salmon when we ate it.

prefrontalon IgNobel Prize in Neuroscience: The dead salmon study (2012)

We just had the one salmon to scan, unfortunately. Regardless of the pre-existing condition of the salmon (zombie, rust, etc) there were no significant voxels of activity once we applied proper statistical corrections. This strongly points to correlated noise as the cause of the uncorrected results.

prefrontalon IgNobel Prize in Neuroscience: The dead salmon study (2012)

Good question. Ultimately, in fMRI we are looking for changes in the local ratio of oxygenated to deoxygenated blood. As neurons begin firing in a brain region more oxygen-rich blood is dumped in by the circulatory system. If the salmon really was responding to the pictures there would need to be blood flow for these changes to be detectable using fMRI. Since the salmon had been prepared by the supermarket there was nothing to circulate blood around.

prefrontalon IgNobel Prize in Neuroscience: The dead salmon study (2012)

At least six, most of them in Cambridge on the night we won the IgNobel prize.

prefrontalon IgNobel Prize in Neuroscience: The dead salmon study (2012)

I am the first author of the salmon poster/paper. If you all have any questions I am happy to answer!

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

My wife and I actually ate it for dinner that night!

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

Glad that you found it useful and/or humorous!

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

We were the inaugural article in what was to be an entire journal dedicated to surprising/odd results. The salmon paper went through a pretty solid peer review as part of publication in JSUR, so we felt good sending it there.

Our paper came out and got a lot of attention, which was good press for the journal. After that the JSUR founders found that they didn't have much time available and the journal folded a few years later. In the end, we were the only paper it published.

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

My grad school advisor and I were always scanning interesting things when we had sequence testing to do. We scanned other objects like pumpkins and such as well. We scanned the salmon since we thought it would look interesting on a high resolution T1 scan. It looked really great in the end: https://www.wired.com/images_blogs/wiredscience/2009/09/fmri...

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

Sorry man - the karma train is probably done. We wrote a few other papers on fMRI reliability, but nothing with the popularity that the salmon paper had.

There are a huge number of fMRI papers that have significant results, statistically and in terms of impact. I have been out of the field for about five years now, so I am not up-to-date with the latest work. I am sure there is some amazing stuff going on.

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

We were doing testing for an fMRI experiment that we planned to run with humans later. So, yes, all of the stimuli were presented to the salmon. It only felt a bit ridiculous at the time...

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

I think it was just asking you to register for Dropbox. If you close that popup the PDF is already open behind it.

Here's a link from my server that should just work: http://prefrontal.org/files/papers/Bennett-Salmon-2010.pdf

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

Yeah, actually, we feel like it did serve as a solid illustration as to why proper statistical correction is necessary. We had a lot of emails saying what a useful tool it was for lab meetings and classes.

We did a review of the literature as part of our paper. In 2008 something like 30% of papers in major journals used uncorrected stats. In 2012 it was under 10%. The field was certainly already moving in the right direction, but I think we managed to help things along.

prefrontalon Risk of false positives in fMRI of post-mortem Atlantic salmon (2010) [pdf]

Yeah! One of the other authors on the paper sent it my way right after it was published. Freaking amazing - I love it.