3 ms·

> Subject: One mature Atlantic Salmon (Salmo salar) participated in the fMRI study. The salmon was approximately 18 inches long, weighed 3.8 lbs, and was not al

> Subject: One mature Atlantic Salmon (Salmo salar) participated in the fMRI study. The salmon was approximately 18 inches long, weighed 3.8 lbs, and was not alive at the time of scanning. > Task: The task administered to the salmon involved completing an open-ended mentalizing task. The salmon was shown a series of photographs depicting human individuals in social situations with a specified emotional valence. The salmon was asked to determine what emotion the individual in the photo must have been experiencing. This is just so, so good. Thank you to this salmon for participating in science.

SubiculumCode 6y ago
The salmon experiment was ages ago, and just showed that the threshold for statistical significance was too liberal. At that time, when neuroimaging was quite new, it was common practice to just pick a threshold, say .001, and not do corrections for multiple tests. That proved to be too liberal. It wasn't a totally stupid guess though. Much of the brain's BOLD activity is correlated, so Bonferroni correction was stupidly conservative (not independent tests). It was only then that newer techniques (cluster-based correction) were adopted, which explicitly made an assumption about the spatial autocorrelation of the data. The one assumption of this technique was that this autocorrelation was the same throughout the brain, which ended up not being a good assumption, though computationally useful. Newer methods today try to model the autocorrelation in the data for cluster based correction, or have moved to other numerical techniques for correction of multiple comparisons re repeated resampling. So, while the dead salmon experiment was eye opening to some when the neuroimaging field was very new, it is no longer relevant now. Neuroimaging techniques are constantly improving, both from better analytical techniques and knowledge about the factors that can compromise the veracity of analyses, but they, including the present paper, show that neuroimgaging is bunk science or useless, which is most certainly incorrect.
- jointpdf 6y ago
  Thanks for this, it was interesting and helpful. My comment was mostly appreciating the sardonic and dry humor in the poster (and the concept of the study itself). It was my first time hearing about this, and it struck me as the type of funny anecdote that could be slipped into a talk/lecture (I find it takes quite a bit of finesse to keep non-technical people engaged when talking about statistics and data science, so humor and relatable examples always help). So, it’s good to know the broader context.

SubiculumCode 6y ago

The salmon experiment was ages ago, and just showed that the threshold for statistical significance was too liberal. At that time, when neuroimaging was quite new, it was common practice to just pick a threshold, say .001, and not do corrections for multiple tests. That proved to be too liberal. It wasn't a totally stupid guess though. Much of the brain's BOLD activity is correlated, so Bonferroni correction was stupidly conservative (not independent tests). It was only then that newer techniques (cluster-based correction) were adopted, which explicitly made an assumption about the spatial autocorrelation of the data. The one assumption of this technique was that this autocorrelation was the same throughout the brain, which ended up not being a good assumption, though computationally useful. Newer methods today try to model the autocorrelation in the data for cluster based correction, or have moved to other numerical techniques for correction of multiple comparisons re repeated resampling. So, while the dead salmon experiment was eye opening to some when the neuroimaging field was very new, it is no longer relevant now. Neuroimaging techniques are constantly improving, both from better analytical techniques and knowledge about the factors that can compromise the veracity of analyses, but they, including the present paper, show that neuroimgaging is bunk science or useless, which is most certainly incorrect.

jointpdf 6y ago
Thanks for this, it was interesting and helpful. My comment was mostly appreciating the sardonic and dry humor in the poster (and the concept of the study itself). It was my first time hearing about this, and it struck me as the type of funny anecdote that could be slipped into a talk/lecture (I find it takes quite a bit of finesse to keep non-technical people engaged when talking about statistics and data science, so humor and relatable examples always help). So, it’s good to know the broader context.