1453: fMRI

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fMRI

Title text: They also showed activation in the parts of the brain associated with exposure to dubious study methodology, concern about unremoved piercings, and exasperation with fMRI techs who won't stop talking about Warped Tour.

Explanation

Functional magnetic resonance imaging (fMRI), as the name suggests, is an offshoot of the MRI. It shows brain activity, typically while the subject is performing tasks or responding to stimuli. During the test, the subject is laid in a relatively small cylinder inside a big, very loud, machine which produces extremely strong magnetic fields. To prevent damage or injury, the subject must remove all metal objects from their body, including piercings, jewelry, watches, etc.

In the tests shown, the brain activity detected is a direct result of the testing environment itself, and has nothing to do with the simple tasks being performed by the subject. During fMRI participants hear loud noises, are confined in a small space (thus the claustrophobia) and have removed their jewelry. The researcher has mistaken these associated brain activities as effects as being caused by performing simple memory tasks which the participants have been asked to do and not a direct result of the settings of the test. Thus, the brain areas described by Megan are those associated with taking a functional MRI scan, rather than those associated with the "test" supposedly being carried out. The results being shown are known as artifacts, which are shown later in 1781: Artifacts.

In real experiments, reported activity patterns are always a result of subtracting average brain activity from many samples gathered during task from so called resting-state activity - which is obtained while subjects are not engaged in any task, thus eliminating the effect the setting has on brain activity. Apparently, the researcher in the comic has failed to account for that in the analysis of the data.

The title text raises the more difficult and controversial issues of methodology, saying that the subjects also showed activation in the parts of the brain associated with exposure to dubious study methodology. Here Randall makes fun of the overly confident, sweeping statements made by some fMRI researchers, often in the press. Of course, fMRI technique requires that the researcher account for several possible sources of errors by, among others, performing proper statistical analyses, multiple comparisons and using proper control groups. These are usually the reasons for fMRI criticism. See the link for further information, including a famous ironic study of a dead salmon which was shown various pictures of people while fMRI scans were made. The scans could be interpreted as showing meaningful brain activity, unless the multiple comparisons problem was properly addressed. Randall has previously made fun of geographic profiles falling to this trap in comic 1138.

The title text then continues with the jewelry issue, now especially the concern about unremoved piercings. In the worst case these could be ripped off by the strong magnetic field. So it could be of some concern - especially when you take into consideration some of the places people may have piercings that are not obvious to the MRI personnel! The final remark about activation regards exasperation with fMRI techs who won't stop talking about Warped Tour. "Warped Tour" refers to a traveling music festival that has been going since 1995, originally as a punk rock festival, but now with a more diverse set of music. Due to the nature of Mosh Pits, the loud, cacophonous music, the facial jewelry of concert-goers and the tight quarters of the pit make it similar in description to an MRI.

Transcript

[Megan talking to an unseen audience in front of an fMRI brain scan.]

Megan: Our fMRI study found that subjects performing simple memory tasks showed activity in the parts of the brain associated with loud noises, claustrophobia, and the removal of jewelry.

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Discussion

" ... and the magnetic field could rip off their jewelry if they are wearing ..." No, I think he's referring to the fact that the subjects were told to remove their jewelry before going into the machine, so that is still on their minds. --RenniePet (talk) 08:10, 28 November 2014 (UTC)

Which they are told because of the fields, which might rip and tear, or just heat up metallic objects... :) --Ergonomist (talk) 10:00, 28 November 2014 (UTC)

Oh come on, it says "the parts of the brain associated with ... and the removal of jewelry". "Removal of jewelry" is something one does oneself. It's not something one typically thinks about as being done to you by magnetic waves. --RenniePet (talk) 10:23, 28 November 2014 (UTC)

Look what the Americans have done to the rather beautiful word 'Jewellery'! I thought it was a horrendous typo by Randall... but no. Lets rip out a couple letters so that a flowing word is reduced to sounding like a sullen teenager. --Pudder (talk) 10:29, 28 November 2014 (UTC)

Do not blame us - its not our fault. The root goes back to 1828, where a linguist named Noah Webster (of Webster's dictionary) laid out a new way to spell words differently in an attempt to differentiate Americans from Britons. It was a whole identity thing, and became extremely popular and took off. Oh well. I always liked the spelling of words with the "ou" in it (colour, etc). On the other hand, "jewellery" just looks rediculous. USA! USA! USA! 173.245.56.215 (talk) (please sign your comments with ~~~~)

Not sure about 'warped tour' referring to 'cognitive confounders'. It's capitalised, so believe that it refers to the travelling music festival; the subject is displaying irritation with the operator constantly talking about their experience at The Warped Tour, just as you would if they were jabbering about last night's TV or the latest boyband. 141.101.98.176 11:07, 28 November 2014 (UTC) IB

The Warped Tour reference may be a scientific in-joke: a key part of algorithms for analyzing MRI data is warping the images so the brain regions are lined up to compare them. Your brain and my brain and every other person's brain are not exactly the same size and shape. So an algorithm identifies key anatomical landmarks and warps the images of each brain to a standard brain map. Otherwise it would be impossible to compare brain scans -- pixels that represent your amygdala might be in the same location as pixels that represent your cerebellum. 108.162.219.221 16:17, 28 November 2014 (UTC)

Here is a small sample of the extensive scientific literature about biomedical image warping methods:

"warping tensors according to the spatial transformation that is calculated between the original and template spaces will also produce inaccurate results by altering the shape of individual tensors, thereby also altering measurements of local diffusivity and distorting inferences concerning tissue microstructure that are based on those measures of local diffusivity" http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2365743/ 173.245.52.125 12:39, 1 December 2014 (UTC)

This is surely an example of the Observer Effect? http://en.wikipedia.org/wiki/Observer_effect_%28physics%29 141.101.98.160 19:31, 29 November 2014 (UTC)

..."In real experiments, reported activity patterns are always a result of subtracting average brain activity from many samples gathered during task from so called resting-state activity" Actually, task activation is generally compared to some other control task or condition, rather than resting state, especially for a short-term memory study such as that referenced in the comic. For example some other task with matched stimulus presentation and response demands (i.e. press a button), but without any memory load. And if rest were used as the implicit baseline, it is extremely unlikely any actual subtraction would be done--rather the so-called resting state would be the implicit baseline state of a multiple regression, in which the task-related predictor variables are convolved with a canonical hemodynamic response function. 108.162.219.118 (talk) (please sign your comments with ~~~~) 108.162.219.118 18:57, 1 December 2014 (UTC)

Also, the concern with unremoved piercings would not be that they could be ripped off during scanning. A participant or patient would not be allowed in the MR room with a dangerous (i.e. large, ferrous metal) piercing, and if somehow one were it would be noticed prior to the initiation of any functional scans (the magnet is always on, so it would be ripped off or otherwise respond to the magnetic field while the participant was being positioned in the scanner bore). Rather, the concern here would be about the piercings heating up during scanning and potentially burning the participant, or potentially causing magnetic susceptibility artifacts in the acquired images (particularly for facial piercings). As precaution it is common to warn participants with unremoved piercings to be attentive to any heating sensation around their piercings and to notify MR technologists immediately if any heating occurs. 108.162.219.118 18:57, 1 December 2014 (UTC)

When I remove jewelry, my main worry is that it will get stolen. 199.27.133.94 (talk) (please sign your comments with ~~~~)