Awesome Article: Dead Salmon + fMRI = ????

Well! I hope you are all prepared for some of the best excerpts I have read since I came across that old paper referring to the “so-called chromosomes”.

This is the paper I am referring to and yes, the Journal of Serendipitous and Unexpected Results is a real journal. The experiment was done in part to determine the false positive rate in an fMRI scan, especially when (as the article states) apparently nobody in the fMRI-using world remembers how statistics works.

…[S]ome researchers would apply correction to some contrasts but not to others depending on the results of each comparison.

So that’s something. It seems that Bennett et al had had enough of this type of carry-on, and proceeded to do something about it:

One mature Atlantic Salmon (Salmo salar) participated in the fMRI study. The salmon measured approximately 18 inches long, weighed 3.8 lbs, and was not alive at the time of scanning. It is not known if the salmon was male or female, but given the post-mortem state of the subject this was not thought to be a critical variable.

Foam padding was placed within the head coil as a method of limiting salmon movement during the scan, but proved to be largely unnecessary as subject motion was exceptionally low.

The salmon was shown a series of photographs depicting human individuals in social situations with a specified emotional valence, either socially inclusive or socially exclusive. The salmon was asked to determine which emotion the individual in the photo must have been experiencing.

This is possibly the most gripping methods section I have ever read, and it’s not even #overlyhonest. Despite the post-mortem state of the subject, some results do occur:

Several active voxels were observed in a cluster located within the salmon’s brain cavity…

Thankfully, once Bennett et al had done the proper real statistics, no more active voxels (brain bits) could be seen.

The Discussion continues to be wonderful:

Either we have stumbled onto a rather amazing discovery in terms of post-mortem ichthyological cognition, or there is something a bit off with regard to our uncorrected statistical approach.

Indeed. It then goes on to describe the dead salmon as “Controlling for the cognitive capability of the subject.” which just gives me a warm, science-flavoured glow in my stomach.

All in all, an entertaining paper about the danger of not correcting for multiple testing and how good statistics is important otherwise you start to draw conclusions like “post-mortem ichthyological cognition”.

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