Talk:Functional magnetic resonance imaging

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[edit] History

I just like to comment on the fact that the history bit on fMRI is a bit misleading here. While Ogawa found the BOLD effect in 1990 by effectively manipulating the oxygen saturation of the blood either directly or by insulin i njections, he merely suggested that this technique could complement PET functional imaging in some way. Of course everyone "knew" this was a possible route to fMRI, Ogawa's group was held back by the fact that they believed the effect could only be observed at high fields > 4T, and their 4T human magnet did not come online till years later. The first fMRI study ever was done by John Belliveau at MGH and published in Science 1991, although it used a paramagnetic contrast agent rather than the BOLD effect. The first BOLD studies came out in 1992, one by Ogawa (PNAS), one by Ken Kwong (PNAS) (there is a wikipedia entry for him already), and one by Peter Bandettini (MRM). —Preceding unsigned comment added by 71.126.226.41 (talk) 05:18, 10 May 2008 (UTC)

I do like the improved history section better than the one I commented on previously. However it would be great if some seminal work was referenced, especially the Bandettini paper: Bandettini PA, Wong EC, Hinks RS, Tikofsky RS, Hyde JS, "Time course EPI of human brain function during task activation" Magnetic Resonance in Medicine 1992 Jun;25(2):390-7. Also, in the context of fMRI, especially since contrast agents are now mentioned as well, the first real fMRI study should be mentioned: Belliveau JW, Kennedy DN Jr, McKinstry RC, Buchbinder BR, Weisskoff RM, Cohen MS, Vevea JM, Brady TJ, Rosen BR. "Functional mapping of the human visual cortex by magnetic resonance imaging." Science. 1991 Nov 1;254(5032):716-9. Last but not least, the original work laying the physical foundation to the BOLD effect was done by Linus Pauling: Linus Pauling and Charles D. Coryell "The Magnetic Properties and Structure of Hemoglobin, Oxyhemoglobin and Carbonmonoxyhemoglobin" PNAS 1936 22:210-216

[edit] boustrophedonic?

Can someone check the meaning of this word? Is this actually used in the fMRI literature? Even if it is, it should be spelled out.

  • Replace! I concur. Definitely not used in MRI literature. —Preceding unsigned comment added by 129.132.154.237 (talk) 14:05, 16 January 2008 (UTC)
  • I don't think it is used. I vote to replace this word.

Boustrophedon literally means "as an ox plows" and refers to the direction of scanning. If the scan is left to right on the first line, then right to left on the second line, etc on alternating lines, then it is boustrophedonic. If the scan is always left to right (like the raster of a TV screen) with silent retrace, then it is not boustrophedonic. Greensburger 14:44, 4 February 2007 (UTC)

I've never heard the word used in reference to MRI (okay, I've never heard the word used at all). I vote for its replacement. Better than that, why not remove the whole paragraph? Maybe we need a separate page describing EPI, which would go into k-space details. There is nothing about fMRI that inherently requires an alternating trajectory, and it seems odd to mention it without first explaining k-space. Reading the section again, the whole section doesn't make much sense. I'm not a functional person, but I guess the section should say something like B0 correction->motion correction->spatial/temporal filtering->correlation to stimuli. Any comments? Arthurtech 18:35, 13 May 2007 (UTC)

A quick search of the journal 'Magnetic Resonance in Medicine' showed no hits for boustrophedon. It doesn't belong here. Arthurtech 20:37, 15 May 2007 (UTC)

Removed. PhineasG (talk) 00:33, 28 May 2008 (UTC)

[edit] Who wrote this page?

Who wrote this page? -Anon

Lots of people, it's a community effort as are all wikipedia pages. Go to the bottom of the article page and you will see a link called "page history", click on it and you will see a list of edits to the page along with who made those edits. theresa knott 20:52, 4 May 2004 (UTC)

[edit] Subtitle of the brain movie is suspicious

Can anyone check that? It should be an MRI video, rather than an fMRI video, even though fMRI information could be superimposed on those frames to get better resolution, which has always been done.

I can't speak authoritatively for all cases, but typically fMRI data is of significantly lower spatial resolution than structural scans. Superimposing functionals is usually done for other purposes than to get better structure, e.g. to allow analysis across temporal/stimulus axes. --Improv 18:31, 9 Mar 2005 (UTC)
Isn't the purpose of superimposing functionals over structurals to see where in the brain the activation is? I guess it's the structural image that must be stretched to match the reference image. --AlmostC 18:11, 1 June 2006 (UTC)

[edit] Is fMRI worthwhile

This is an important section and should be included, people need to be made aware of the fundamental arguments which underlie functional imaging. (and no, those references weren't mine).

  • I agree; it is important to mention the criticisms against fMRI raised by other scientists, and even if the section needs some work it shouldn't be deleted. Gccwang 04:02, 1 January 2006 (UTC)
There are clearly debates over the proper design, analysis, and interpretation of fMRI studies. However, I don't believe there is any serious doubt in the neuroscientific community that the technique itself is tremendously useful. As is stated in the current version of this section, fMRI is only as useful as the experiment designed around it, as with any other technique. Thus I've changed the title of this section to better reflect the general (scientific) consensus. PhineasG (talk) 00:38, 28 May 2008 (UTC)

[edit] What are "hemodynamic signals"?

It would be nice to have a potted description of the "hemodynamic signals" that appear in the first paragraph.

Sadly, the entry elsewhere on "hemodynamics" isn't much help, which may explain why it isn't linked from here http://en.wikipedia.org/wiki/Hemodynamics.

Michael Kenward

[edit] "CBF"

Near the end of the third paragraph, what is "CBF"? Is it "cerebral blood flow"?

Lance ==)------------


Yes.

[edit] New research

Recently, a report was published in the Proceedings of the National Academy of Sciences documenting a "brain-training" session with both healthy and chronic-pain volunteers who studied their own brain activity while being "instructed" in useful ways to minimize pain perception and were able to significantly reduce pain after a mere 39 minutes of practice in the machine. This was contrasted with control and comparison groups who either were not in the machine, were given others' brain data, were instructed in various biofeedback techniques or were given data about a different section of the brain than that thought to control pain perception. Those who were being presented with data from their own rostral anterior singulate cortex in real-time during their training session reported reductions in experienced pain of more than half, while the other groups did not.

To me, this seems worthy of inclusion in the fMRI article, perhaps alongside a section about possible future uses, or at least noteworthy current experiments.

Also, is this phrase in need of a change or addendum? "To this date, fMRI has neither proven therapeutic value nor known damage to the human body."

67.171.194.78 04:53, 25 December 2005 (UTC)

  • Let's wait for it to settle down as being an established scientific fact. This is too new to be considered reliable, and there hasn't been time for followup studies and criticisms to be published yet. If in 6 months it's considered well-founded, then it may be worthwhile to include. --Improv 05:02, 25 December 2005 (UTC)
    • Perhaps just a category for current research? It seems some examples should be presented, even if they're general. 67.171.194.78 05:10, 25 December 2005 (UTC)
      • There's always a lot of research being done on this. If we dip our toe into those waters, we'll be kept impossibly busy covering facts that are distant from being accepted science. --Improv 06:11, 25 December 2005 (UTC)
  • I agree with Improv here: there's just too much fMRI research going on for a "current projects" section. Semiconscious 06:16, 25 December 2005 (UTC)
  • The author (Christopher deCharms) actually started a company (omneuron.com) to implement this neurofeedback technique, which to me is promising. A similar work is by Rainer Goebel (inventor of BrainVoyager), where ping-pong balls in a game are controlled by such biofeedbacks read from fMRI of visual cortex. In my view, these works represent a growing branch and are worth included into the current research section. By all means, if such serious work is "distant from accepted science" (User:Improv), the "fMRI lie detector" is at a much longer distance from any serious science, and shall be deleted.--Schlieren 04:05, 11 July 2006 (UTC)

[edit] Article removed from Wikipedia:Good articles

This article was formerly listed as a good article, but was removed from the listing because the article fails to cite and references. --Allen3 talk 11:52, 16 January 2006 (UTC)

[edit] Comparisons to PET

Could a comparison to PET (in terms of resolution, cost, safety, usage, etc.) be included somewhere on the page? I'm no expert on either, but it seems like this would be a natural thing to include given that both tecnologies try to measure CBF. 128.42.167.200 20:33, 11 April 2006 (UTC)

Good idea. MEG and EEG would be other good comparison targets. There's a figure in circulation (most textbooks) comparing spatial and temporal resolution of functional imaging techniques. I'll try to find/post it without treading on copyrights. --Josh Powell 00:04, 9 July 2006 (UTC)

[edit] Pharmacological challenge functional MRI

I don't see any entries for p/ph-MRI. Am I looking in the wrong place, or has nobody written an article yet? Jddriessen 14:30, 14 April 2007 (UTC)

[edit] Event-related fMRI

I'm new to Wikipedia and just created my first article, efMRI. In retrospect it should be part of this article. How do I do that?


Abe (or Abraham) 03:08, 12 September 2007 (UTC)

[edit] Merging

  • These articles should really be merged under the heading BOLD fMRI which is both more accurate and comprehensive. Other existing and emerging MRI techniques are also referred to as "functional MRI" but with respect to gastric function, muscular function or even brain function revealed by mechanisms other than the BOLD effect e.g. arterial spin labeling (ASL).
  • Regarding merging with Real-time fMRI: I think Real-time fMRI should be its own article. It is sufficiently large. fnielsen 15:21, 16 November 2007 (UTC)
  • Real-time fMRI is only one paragraph, excluding reference. It should be merged into the main article. BOLD should also be merged in. If they grow within the article, then perhaps they can be summarized within the article and described in detail in their own articles. -kslays 19:50, 3 December 2007 (UTC)
  • Regarding merging with Real-time fMRI: I think Real-time fMRI should be its own article. It is a distinct area of the field, and significant advances are underway
  • Merged the one paragraph from BOLD into this article and redirected the BOLD article to here. I removed the merge suggestion tags Kpmiyapuram (talk) 16:57, 2 April 2008 (UTC)
  • I'd like to re-open the suggestion to merge Real-time_fMRI into this article. I know RT fMRI is an active area of research, but then so are most other areas of fMRI. I don't think a single paragraph justifies a separate article, but I do think it would be good to mention RT fMRI here, to give the casual reader a chance to find it. GyroMagician (talk) 09:58, 12 August 2008 (UTC)

[edit] Newsweek article on fMRI mind reading

Check this out. I am very skeptical, but it's in the press, so people will look at the wiki article for further info. L'omo del batocio (talk) 11:07, 10 February 2008 (UTC). The PloS ONE article is available here. L'omo del batocio (talk) 11:50, 10 February 2008 (UTC)

[edit] 2 citations

Only 2 references? --1000Faces (talk) 02:48, 28 February 2008 (UTC)


[edit] Beyond Blobology

Perhaps it should be mentioned that there is some kind of critizism about "Blobology" and the scarce interpretation of the pictures generated (as far as I understand it), see for instance: http://www-bmu.psychiatry.cam.ac.uk/sitewide/publications/presentations/bullmore04mul.pdf - this Term slowly dissipates into German for instance, as "Blobologie" Plehn (talk) 09:54, 9 April 2008 (UTC)

[edit] Advantages and Disadvantages of fMRI

I've hacked around at this section a bit, but it's still not great. It reads like an aggressive put-down of a worthless technique. The "advantages" section is begrudging at best, while the "disadvantages" section is extensive and broad. Would somebody (maybe with a little more experience in fMRI use) like to rewrite this section to make it a bit more balanced? GyroMagician (talk) 13:43, 9 August 2008 (UTC)

[edit] Commercial Use

The "commercial use" section seems to be pretty low value random collection of links, only really advertising a few companies involved in fMRI and linking to someones blog. I'd like to delete it. What do you think? GyroMagician (talk) 10:33, 12 August 2008 (UTC)

Nobody disagreed so I thought I'd be bold - it's gone ;-) GyroMagician (talk) 22:40, 25 August 2008 (UTC)
It went a bit too fast for me. I agree that the collection of links was not good. However, I like the section and I have reestablished the section and now put in some more context. It could still need and rewrite and cleanup. — fnielsen (talk) 07:25, 26 August 2008 (UTC)
It looks better now, nice edit. I'm not so sure about the 'other modalities' section - maybe move to 'related techniques'? As a kind-of related question, who is Christopher deCharms and does he require special mention? GyroMagician (talk) 11:29, 26 August 2008 (UTC)
I have moved the "other modalities" section to "related techniques" and to the MRI article. I have not heard of Christopher deCharms before I read of him on Wikipedia and I do not know if he requires special attention compared to founders of the other firms. — fnielsen (talk) 12:31, 26 August 2008 (UTC)
I like it ;-) I hope you don't mind my minor tweaks - I removed the reference to C.deCharms and made a couple of other minor changes. GyroMagician (talk) 14:50, 26 August 2008 (UTC)

[edit] Article Images

I removed two images from the article. They are both reasonably high res. structural MRIs, while the article is about fMRI. We all like pretty pictures, but let's try to keep them relevant. To maintain the cosmic balance and keep some images in the article, does anyone have raw EPI's (i.e. low resolution, as acquired for fMRI) and maybe timecourses, to illustrate the functional part in fMRI? GyroMagician (talk) 22:14, 4 December 2008 (UTC)

[edit] Realtime

Under "Realtime fMRI" I linked to realtime computing. I would link to a generic realtime page, but one doesn't exist. However, I don't think RT-fMRI is possible with RT computing, and that page discusses the relevant concepts. To quote from the first paragraph:

In computer science, real-time computing (RTC) is the study of hardware and software systems that are subject to a "real-time constraint"—i.e., operational deadlines from event to system response. By contrast, a non-real-time system is one for which there is no deadline, even if fast response or high performance is desired or even preferred.

While RT-fMRI might have different requirements to more traditional RT applications (something like an engine timing controller), it does have a definite deadline to meet (data must be available by a certain time to control stimulus presented to the subject). GyroMagician (talk) 09:22, 5 December 2008 (UTC)

Hi, I just removed that section -- sorry, I didn't see this note or I would have discussed it with you here before doing so. I left a note on your talk page explaining the reasons for removing it: basically, weakness of the sources combined with theoretical unlikelihood that anything like current fMRI has a good enough signal-to-noise ratio to be used in this way on a regular basis. As I said, I'm open to discussion on this matter, but feel that if the section is to stay, at the least better sources ought to be found. Looie496 (talk) 17:13, 5 December 2008 (UTC)


[edit] FMRI in popular culture

The generally cool and otherwise seemingly realistic book "Daemon" by Leinad Zeraus mentions the use of fmri as a type of lie detector to probe the head and emotions of an applicant during 48 hours before accepting him. Is this even remotely possible, such as distinguishing "happy" from "angry" in an FMRI, and should the book maybe be mentioned here then? Please ping me or something with comments, I'm new and don't know how to monitor pages like this CarlJohanSveningsson (talk) 12:25, 8 January 2009 (UTC)

There has been discussion of things like this but it will require major advances to be realistic. For one thing, a subject in an fMRI scanner is surrounded by tons of machinery and confined to a narrow space that makes many people claustrophobic, and while the machine is running it generates continuous extremely loud banging noises, so the scanning process itself is likely to generate strong negative emotions. Secondly, the signals that fMRI picks up are very weak and noisy, so probes generally have to be repeated many times in order to give a usable signal. But theoretically such a thing is not out of the question. I have never heard of the book you mention and don't know whether it is notable enough to discuss here. Looie496 (talk) 17:55, 8 January 2009 (UTC)
Mainly, what he said ^^^^. There have been some studies trying to detect people lying, but it's a bit of a strecth - probably less accurate than galvanic skin response (i.e. not at all). I don't think it deserves comment on the main page - the page is already long, and there is far more to be said on other topics. If you'd like to read more about the topic, Google is bountiful. GyroMagician (talk) 17:45, 9 January 2009 (UTC)
Old topic, but thanks for exhaustive answers! Just as a note, Suarez and maybe the BBC (popular science? :-P ) are not quite letting go of the topic. In "the technology in Daemon" ( http://www.thedaemon.com/daemontech.html ) is linked to a BBC article that "scientists can read your mind" ( http://news.bbc.co.uk/2/hi/health/4472355.stm ). Does a scanning physically have to be that bulky, or is it slimmed down with development, is the report mentioned by BBC fabricated crap, or where's the fiction slipping in here? Thanks CarlJohanSveningsson (talk) 20:29, 30 June 2009 (UTC)
Happy to help! MRI scanners are not getting a lot smaller anytime soon, especially those suitable for fMRI (which require a strong magnet to have enough sensitivity). The biggest part is the magnet, which has to be supercooled (i.e. immersed in liquid helium). The magnet is also pretty strong, so it needs to be kept in its own room to prevent it 'picking up' nearby chairs/beds/computers/etc. It is possible that in the future another imaging method will become sensitive enough to 'read minds' (maybe something like NIRS) - something that can be miniaturised more easily - but I think it is unlikely that an MRI system will ever get that small. The power supply is also pretty hefty. GyroMagician (talk) 08:28, 1 July 2009 (UTC)

[edit] Physiology of BOLD

I suppose there's frequently repeated error present also in this article. rise in cneural activity DOES NOT cause increase but DECREASE in local oxygen consumption (due to that neurons switch to more rapid glycolysis, thus they need less oxygen). See Raichle (2006) Historical and hysiological perspective. In: Cabeza R. & Kingstone A (eds.) Handbook of functional imaging of cognition. MIT Press. —Preceding unsigned comment added by Pamejudd (talk • contribs) 21:34, 11 January 2009 (UTC)

[edit] diffusion fMRI

Hello Afiller and all. The last paragraph in the background section discusses diffusion as a functional method. This is a neat trick if it works, but I'm not sure it belongs in here. Is it an accepted method, or a current research topic? Does anyone know how many groups are using it? As the paragraph currently reads, I would expect BOLD fMRI to disappear in a few years. The rest of article is currently about BOLD, which fit well with current practice. Maybe discussion of functional diffusion imaging would be better placed as a section under 'related techniques'? GyroMagician (talk) 08:24, 4 June 2009 (UTC)

I would agree with that. In fact I just deleted the sentence stating that diffusion fMRI may become important in future just to cite Aaron Fillers' recent article reviewing his own view of history altogether. This page should be informative about fMRI, which consists mainly of BOLD. I think alternative approaches can and should be mentioned, but then they should be clearly marked as such in a separate section. Just to make this clear, this is not meant to disrespect Dr. Fillers work, its simply not the right place and not the right time for these statements. The idea itself is clearly laid out in LeBihan's article, and the Filler review elaborates on it from a historical perspective (although its practically a look into the future) without providing any kind of evidence. The method has not really been validated by other groups, in fact at the 2007 ISMRM meeting in Berlin, two independent groups presented evidence to the contrary in oral presentations. That being said the last word is not spoken, and it may yet be that this method turns out to be useful, at which point more about this should be included in wikipedia with references to peer-reviewed literature.—Preceding unsigned comment added by 76.24.22.31 (talk) 01:41, 20 July 2009 (UTC)

[edit] fMRI fact vs. speculation

I know its much easier to complain about something, than to fix it, and I intend to help a bit, but its a bit disappointing that there is lots of opinion/speculation on this papge without references. The neural correlates of BOLD section, which some would view as one of the most important on a page about fMRI/BOLD, has virtually no references and dwells on the use of the "initial dip" transient response, without reference and claims that it has achieved certain feats. This method is not mainstream and pushed mainly by one group and few others, the results are appealing and the authors are respected members of the community, however like many things in research, everything needs to be subject to validation, which has not happened in this case (unfortunaly rarely happens in fMRI, but thats another topic). I think stuff like this needs to be presented a lot more carefully, especially so that it is clear for the layman wanting to learn about fMRI what is commonly accepted "fact" and what is subject of research/opinion of few. Sorry for the ramble, just wish the page would get better :-)

Funny, I'd never noticed how lacking in citations this page is. You're correct, we need to add some. I think that process will help to shake out the speculation and improve the text. I agree with you that this page should reflect current practice, rather than listing every obscure technique ever considered. Given the amount of media attention fMRI continues to receive, we should have a good lay explanation, making the limitations of fMRI clear. The initial dip paragraph should be pulled out into its own section. I still thin the "Advantages and Disadvantages" section needs work too (but I can't quite see how to fix it). There are very real limitation to fMRI, but the section reads like a nit-picking rant. Shall we see if we can improve things? GyroMagician (talk) 07:36, 20 July 2009 (UTC)

[edit] Oxygen and Glycolesis

The article has just been edited to change decrease to increase in the following:

When nerve cells are active they increase their consumption of oxygen, switching to less energetically effective, but more rapid anaerobic glycolysis.

That doesn't make sense to me. If the glycolysis is anaerobic, shouldn't the oxygen consumption go down rather than up? Or is there another mechanism at play at the same time? GyroMagician (talk) 20:14, 18 August 2009 (UTC)

[edit] confusing

The passage;

When nerve cells are active they increase their consumption of oxygen, switching to less energetically effective, but more rapid anaerobic glycolysis. The local response to this oxygen utilization is to increase blood flow to regions of increased neural activity, which occurs after a delay of approximately 1–5 seconds.

confuses me. If a process is "anaerobic", how would it increase oxygen usage? Perhaps this is just my own ignorance. —Preceding unsigned comment added by 97.115.243.241 (talk) 12:13, 12 September 2009 (UTC)

[edit] Head Movements

Does anybody have an article source for the 3 mm limit of the head movements? I learned it is related to the voxel resolution of the volume (3x3x3 in most cases) and due to limits of the used methods, but I am lacking a quotable source.

Thanks in Advance. —Preceding unsigned comment added by 141.35.245.181 (talk) 19:19, 19 November 2009 (UTC)

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