Talk:Functional magnetic resonance imaging/Archive 1

Page contents not supported in other languages.
From Wikipedia, the free encyclopedia
Archive 1

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

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)

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)

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)

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)


Can anybody site a single instance where fMRI has revealed something previously unknown about brain functioning. I am not asking for references to the bazillion fMRI articles that have CLAIMED new insight. I want confirmation of new insight or of new phenomenon that might lead to new theory with respect to brain functioning. —Preceding unsigned comment added by Quadruplecheck (talk • contribs) 07:20, 7 June 2010 (UTC)

First of all, it's "cite", and "phenomena". Second, use Google Scholar if you want "confirmation". There's a lot of stuff out there.
And stop trolling.Isthismetal (talk) 19:29, 24 September 2010 (UTC)

So what you are saying is that you can't answer this extremely important question. —Preceding unsigned comment added by 128.32.52.185 (talk) 19:16, 14 October 2010 (UTC)

--- Regarding the "general (scientific) consensus" mentioned above: I do not believe there is a general neuroscientific consensus regarding the utility of fMRI. Certainly, within the echo-chamber of the fMRI community, there is consensus. However, among physiologists working from slice to primates, there is real concern over the validity of this technique and its underlying (often unrecognized) assumptions. I would add at least these additional potential disadvantages:

  • BOLD measurements have only relative, not absolute, values. Therefore, any claimed neural signal is really the subtractive result across two conditions. This is fundamentally different from other physiological measurements which observe absolute events (e.g., a spike is a spike - no subtraction across conditions required). This is a fundamental limitation of the technique, as it requires the extra step and assumptions of a subtractive experimental design. This is especially problematic when it comes to "higher" cognitive functions, where it may not be a given that the difference between two conditions is not something unexpected. — Preceding unsigned comment added by Thinkpinkink (talk • contribs) 16:47, 2 November 2011 (UTC)
  • There is no discriminatory ability when it comes to metabolic activity resulting from increased inhibitory vs. excitatory activity. Thus it is possible that the more highly active inhibitory neurons could result in a BOLD response that is mistaken for activation of an area, whereas in reality that area is being "clamped down" by inhibitory activity.
  • There is recent evidence that increased MUA and LFP activity in some subcortical structures might be associated with decreased CBV and decreased BOLD responses (Mishra et al, J. Neurosci, 2011 31(42):15053-15064). Therefore, one must contemplate the possibility that each particular brain area may have its own transfer function between neuronal activity and the resultant BOLD measurement.

I wold also remove the "unlikely" parenthetical with regard to the possibility that BOLD measurements reflect synaptic inputs (LFP) without direct correlation of spiking outputs, as this is opinion, and not based on data.

These are not trivial details. These speak to the fundamental validity of this tool (fMRI) in its current form as applied to understanding neuronal activity.

As for the commenter above who mentioned the idea that nothing "previously unknown" has resulted from fMRI work: That may be a bit overstated. However, it is not unreasonable to propose that the independent contribution of fMRI to our understanding of the brain is much more limited than is usually appreciated. In our experience, fMRI studies do not usually predict what one will see on the single unit level. However, the apparent confirmation of single unit studies by subsequent fMRI appears robust - but this may reflect a selection bias in the literature, as it is unlikely anything that contradicts single unit results will gain much traction. — Preceding unsigned comment added by Thinkpinkink (talk • contribs) 14:53, 2 November 2011 (UTC)

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)

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)

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)

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)

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)

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)

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)

2 citations

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


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)

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)

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)

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)

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)

Why is there no information about real-time fMRI? I do research on real-time fMRI and it's almost considered as a field of its own. — Preceding unsigned comment added by Wanderine (talk • contribs) 19:48, 17 July 2011 (UTC)


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)

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)

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)

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)
I've added some sources to the BOLD section. Also for the "initial dip", but I agree that it is pretty speculative and experimental as far as measuring it with BOLD is concerned; or at least it used to be regarded as such by many when I was writing my thesis. It's existence seems pretty well established by at least nine papers, two of which in very highly respected journals (Science and Nature Neuroscience, see http://www.sciencemag.org/cgi/content/abstract/272/5261/551 and http://www.nature.com/neuro/journal/v3/n2/abs/nn0200_164.html respecticely). The Malonek and Grinvald article is particularly convincing as they measured the flow more directly and thoroughly through optical means. Measuring it reliable with BOLD is a bit more tentative, but there seems to be some interesting recent work on it as the article about caffeine cites quite a few papers I haven't seen before so perhaps the Kim et al results have been reproduced by more groups. Maybe someone with more recent experience with the literature can comment on this as I haven't really looked into the subject the last few years. Smocking (talk) 19:44, 14 February 2010 (UTC)

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)

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)

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)

There is no "limit" for head movements. There are various methods for correcting for and "fixing" artifact due to head
movements, but there is no threshold beyond which the data must be unequivocally discarded. Isthismetal (talk) 02:27, 2 August 2010 (UTC)

MRI imaging and using dye.

Bold textI am presently going to have a MRI next week and last time when I used the dye it made my underlying condition more severe. I need to show the neurologist that I have vasculitis in the brain and I am wonder if that will show without the dye. Also I would like to know if I had T2 hyperintensity flaring in the brain and now it has slowed down would there be any liasions or footprints or scaring showing how bad it was a week before. Last of all when your nervous system is having symptons like MS when it is attacked in the spine is the any scar tissue present if they do a imaging of the spine without dye as well. Having MRI next week and need to know please. Thanks —Preceding unsigned comment added by Bootie126 (talk • contribs) 20:01, 19 February 2010 (UTC)

Editors on Wikipedia are not permitted to answer medical questions, and it would be foolish you trust an answer you get from an anonymous editor anyhow. Looie496 (talk) 22:00, 19 February 2010 (UTC)
(edit clash with Looie - I'm basically giving the same answer) Sorry, but we can't offer medical advice here. For example, I'm a physicist - I could tell you all about spins, but I can't even tell when a brain is upside-down. I can tell you that the 'dye' is often called a 'contrast agent'. Contrast agents are sometimes used - it depends what the scan is meant to show. The best person to ask about this is the your neurologist - ask for an explanation of what will happen, and what he or she is looking for. Good luck with the scan - I hope it help. GyroMagician (talk) 22:11, 19 February 2010 (UTC)

Usage in Lie Detection

The only source in this article that mentions the usage of fMRI in lie detection refers to MythBusters, of all things, and doesn't even properly cite that. I've deleted the sentence on MythBusters as I think it is highly irrelevant as a serious source, and replaced it with a summary of a couple of peer-reviewed papers, which are properly cited.

There is plenty of serious literature on this topic, so I really don't see why we need a MythBusters reference. -Ferahgo the Assassin (talk) 19:18, 31 May 2010 (UTC)

The following makes no sense:

The signals are extrapolated from the fMRI machine onto a screen, displaying the active regions of the brain.

What are you trying to say here?
Also, while I agree that MythBusters isn't the perfect source, you have taken a section that was very skeptical about lie-detection using fMRI and made it glowingly positive. Maybe some balance would help? GyroMagician (talk) 19:44, 1 June 2010 (UTC)
Oh, I didn't write that part. That was just left over from the previous edit, I didn't bother deleting it along with the Mythbusters stuff. I agree that part's a little badly worded also.
I added what I did because I knew of those two specific papers right off the bat, but I can certainly find some additional papers to balance things out if you'd like (or someone else can). This entire section could likely use a little clean-up. Do you think that lie detection should have its own section in general, or is it fine the way it is under commercial usage? -Ferahgo the Assassin (talk) 20:34, 1 June 2010 (UTC)
Sorry, my bad - and your rewrite looks much better. From an MRI perspective, I think lie detection is a niche application, and can stay where it is in the article. I wouldn't like to see a minor, but press-grabbing, application take up too much space. However, based on a very quick search I tried last night, it might be cooking up a storm in the legal ethics world, so maybe it's a section that will grow in time. GyroMagician (talk) 07:00, 2 June 2010 (UTC)


Disadvantages of fMRI - The Salmon experiment.

"Unfortunately, this case is not particularly instructive as it does not mirror those of human experiments, which average across many participants. Averaging across participants generally corrects for the likelihood of observing random activation in a truly inactive voxel x, because activation needs to be observed across most (or all) participants to appear significant at the group level. The chance of voxel x surviving the threshold across most or all participants is much lower than the chance of it surviving threshold in any 1 participant. Were the experiment repeated with 15 or 20 salmon (say), and a group average revealed significant activation in certain voxels, then that would be cause for concern that current methods do not control the false positive rate strictly enough. The salmon experiment as it stands does not constitute good evidence in favor of the conclusion most closely associated with it." Originally written by user 140.247.11.52 as a comment in the article, copied to Talk page by: Lova Falk talk 16:01, 14 June 2010 (UTC)

Averaging across participants does generally not correct for the likelihood of observing random activation. The standard random effect analysis still has the multiple comparison problem. — fnielsen (talk) 18:54, 14 June 2010 (UTC)
As the author of the salmon paper on multiple comparisons I can comment directly on its utility. The fish results were always intended to be a salient illustration of why multiple comparisons correction is necessary in fMRI, not as a proof in and of itself. The statistical necessity of proper correction had already been established in the literature for over a decade. The above quote was a footnote from a paper by Lieberman and Cunningham in 2009. In the paper they argue for looser control of false positives to prevent against Type II errors (missing legitimate results). If they could back up the above point statistically I would give them credit, but they have shown no data demonstrating that group results are less noisy than individual results. PrefrontalX (talk) 21:46, 4 March 2011 (UTC)

History again

I've tried to tidy up the history section a bit, to keep things chronological. I have also removed the following (recently added) section, because I don't see why it belongs there:

The first paper conducting the analysis of a sequence of functional images by using correlation maps was submitted by Jadwiga Rogowska at the [[Massachusetts General Hospital]] Center for Imaging and Pharmaceutical Research on January 14, 1992, revised March 17, accepted April 6 and published in the September issue of the [[Journal of Computer Assisted Tomography]].<ref>{{Cite journal | author = Rogowska, J. and Wolf, G. | title = Temporal Correlation Images Derived from Sequential MR Scans | journal = Journal of Computer Assisted Tomography | volume = 16 | pages = 784-788 | year = 1992 | doi = http://journals.lww.com/jcat/Abstract/1992/09000/Temporal_Correlation_Images_Derived_from.21.aspx }}</ref>

If I'm wrong, please put it back ;-) GyroMagician (talk) 09:39, 23 June 2010 (UTC)

Merge proposal

What shall we do with the POV-ridden essay Issues in fMRI? I propose a merge to "Disadvantages" section or plain redirect it here. (Listing here for more eyes to look at) Kimchi.sg (talk) 09:57, 8 August 2010 (UTC)

If you can find anything useful in there, please merge into "disadvantages" as you suggest, but it does look like a rather long, ranty article about why fMRI is no good (why does fMRI inspire those?). GyroMagician (talk) 14:28, 8 August 2010 (UTC)
That's a terrible article. A couple of things mentioned (e.g. incidental findings, neuromarketing) are not even disadvantages or issues of fMRI. Other things mentioned (e.g. signal drift) are well-known and easily corrected. It seems like a half-baked review and intro to fMRI for new researchers. It should probably be scrapped.Isthismetal (talk) 19:22, 24 September 2010 (UTC)
It is. I've found the best way to remove a bad article like this is the chip away, section by section, and copy across any good information to the parent article. I've deleted two sections - now it's your turn ;-) GyroMagician (talk) 20:35, 24 September 2010 (UTC)
Ok, I've deleted two sections (and added two small bits to the main entry). I guess you're up now! Isthismetal (talk) 17:01, 30 September 2010 (UTC)
Aaaaand, I got greedy and got rid of 2 more sections...Isthismetal (talk) 17:17, 30 September 2010 (UTC)

website

http://en.wikipedia.org/w/index.php?title=Functional_magnetic_resonance_imaging&oldid=224198848 —Preceding unsigned comment added by 67.82.134.140 (talk) 18:58, 12 March 2011 (UTC)

GA Review

GA toolbox
Reviewing
This review is transcluded from Talk:Functional magnetic resonance imaging/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Crisco 1492 (talk · contribs) 14:58, 9 February 2012 (UTC)

I will be doing reviews of referencing and whatnot before prose, as I find it pointless to review prose if/when the article has many other issues.

Checklist

Rate Attribute Review Comment
1. Well-written:
1a. the prose is clear, concise, and understandable to an appropriately broad audience; spelling and grammar are correct.
1b. it complies with the Manual of Style guidelines for lead sections, layout, words to watch, fiction, and list incorporation. Tone issues rampant
2. Verifiable with no original research:
2a. it contains a list of all references (sources of information), presented in accordance with the layout style guideline. Page numbers for numerous footnotes missing
2b. reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose). Numerous unreferenced paragraphs
2c. it contains no original research. Linear addition from multiple activation section is terribly undersourced, giving the impression that it is OR
3. Broad in its coverage:
3a. it addresses the main aspects of the topic.
3b. it stays focused on the topic without going into unnecessary detail (see summary style).
4. Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each.
5. Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute.
6. Illustrated, if possible, by media such as images, video, or audio:
6a. media are tagged with their copyright statuses, and valid non-free use rationales are provided for non-free content. Good
6b. media are relevant to the topic, and have suitable captions. Good
7. Overall assessment. Pending

Referencing is far under par. Failed. Crisco 1492 (talk) 15:04, 9 February 2012 (UTC)

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

Timestamping. 68.126.183.202 (talk) 19:18, 15 February 2012 (UTC)

Neuron energy source?

"They [neurons] even do not have the capability to generate the energy for themselves and are fully dependent on glial cells, which provide the service" - I came here to read about fMRI but found this statement odd. Neurons can utilize glucose in situ. Furthermore, I'd argue that if the author is refering to the production of lactate by glial cells which neurons can use as an energy source, they still utilize mitochondria to generate ATP from the lactate.

I would change it myself but don't really know how...Cheers

Timestamping. 68.126.183.202 (talk) 19:17, 15 February 2012 (UTC)

"CBF"

Near the end of the third paragraph, what is "CBF"? Is it "cerebral C.R.A.P flow"?

Lance ==)--


Yes. Try to force archiver by timestamping 68.126.177.110 (talk) 04:32, 7 March 2012 (UTC)

fMRI Usage in court cases. Should it be allowed?

fMRIs are the latest form of lie detection and they are said to be 90% accurate because they can determine if a person is lying or telling the truth based upon a scan of the person in question’s brain. fMRIs are said to detect lies by seeing inside of the brain rather than tracking the peripheral measures of anxiety (changes in pulse, blood pressure and perspiration) which are measured by the age old polygraph machine. In 2008 there were two companies willing to take on the task of performing fMRI scans they were Cephos in Pepperell Mass. and No Lie MRI in Tarzana California. The two companies claimed that they could predict with 90 percent or greater certainty whether the person receiving the scan was telling the truth or not. Many neuroscientists and legal scholars doubt the claims of being 90 percent correct and some question whether the brain scans for lie detection will ever be ready for anything other than more research on the nature of deception and the brain. fMRI machines are able to track the C.R.A.P flow to activated brain areas. The assumption in lie detection is that a brain must exert extra effort when telling a lie and therefore the regions that do more work will receive more blood. The areas then light up during the scan, the illuminated regions are primarily involved in the decision making process. Studies to find out if the fMRI really is accurate have been being performed for years now. However there has been no study proving that fMRI scans can really prove that a person is lying. With having no evidence to prove that an fMRI can accurately prove that a person is lying, the controversy as to whether the data from an fMRI should be allowed as evidence in court has become a popular topic. fMRI data has been used as evidence in court cases a number of times but it has never been allowed to be used as a form of lie detection. There have been several attorneys who have tried to submit lie detection data from fMRIs into evidence and the judge has dismissed them. The lie detection portions of the fMRI scans are a new thing and judges aren’t going to use them to help aid in a conviction until there is without a doubt no question on the accuracy of the scan. The fMRI can see the brain directly when questioning the person whereas the polygraph can be finagled by the person receiving the test. I have seen first hand where the polygraph can be thrown off by the simplest change in demeanor of the person in question. Murderers are smart enough to find a way to cover their crimes therefore they are probably smart enough to skew the results of the polygraph test therefore escaping the fate they are owed. Using a scan that can see the brain’s response immediately after asking a question will make it harder for someone to alter the test results. Simple cases I feel do not warrant the costly fMRI scans, but the scan would be very useful in cases that are complex. In cases such as the Casey Anthony trial and the trial against Michael Jackson’s doctor fMRIs would have been a very useful technology to use to determine if they should have been found guilty or not guilty. As with anything the fMRI also has its faults. The cost of the fMRI scan is outrageous. In order to run the test a scanner must be purchased which cost over $1,000,000 and the procedure itself costs anywhere from $450 to $3,500. If the testing is used as evidence into a court case who would be the one responsible for paying for this scan to be performed, would the defense be responsible or would the prosecutors be reliable if they are the ones submitting the data? One of the major problems of the testing done to determine the accuracy of the fMRI is being able to test the brain’s response to a question comparable to one that would be asked during a trial. The brain does not respond in the same way in a mock setting as it would in the real deal making the researcher’s jobs that much harder to prove that the fMRI is worth it. Whether fMRI scan data should be allowed to be entered into evidence in a court case is something that is always going to be a controversy. Hopefully researchers will be able to prove the accuracy of the fMRI scans within the next few years so that the new lie detection technology can be used and help determine the innocence or guilt of a person on trial. It may take years before the fMRIs can be thoroughly vetted as lie detection machines. However if they are really found to have 100% accuracy would the courts be willing to accept them? Forensic scientists have given us reliable evidence before and we depend on it not only for safety but for justice as well. Truth and lies, however, have always been something like beauty, always changing in the eye of the beholder. Is there any way we can really scientifically qualify something to be a lie or dub it the truth? Or will we only be able to say that someone is using their brain is the same way as another person does when they tell a lie? Even if the fMRI lie detection becomes 100% reliable there will be people who are loath to place justice in the hands of a machine. Over the next few years one thing that seems certain is that there is sure to be more conflicts due to this new technology.

Timestamping. 68.126.183.202 (talk) 19:17, 15 February 2012 (UTC)
Highly unlikely that anybody is going to try to read that huge unstructured text mass. Could you summarize your point in a couple of sentences, please? Looie496 (talk) 19:53, 15 February 2012 (UTC)
I am not the author of that stuff. All I am trying is to get the archiver to shelve this. Didn't want to explicitly edit the talk page. 68.126.183.202 (talk) 21:12, 16 February 2012 (UTC)

Order of initial human fMRI studies

The Huettel text is quite clear: "The first study, by Kwong and colleagues, used . . ." "These findings were replicated in a similar study published the following month by Ogawa and colleagues . . ." Both studies appeared in the same publication: PNAS. Kwong's in 89(12) (pp 5675-79) and Ogawa's in 89(13) (pp 5951-55). — Preceding unsigned comment added by 68.126.185.32 (talk) 05:46, 6 March 2012 (UTC)

I'm no fMRI expert, but I thought these two articles by Ogawa et al were considered the first publications on the topic:
Oxygenation-sensitive contrast in magnetic resonance image of rodent brain at high magnetic fields, Magnetic Resonance in Medicine, 14(1), pp68–78, April 1990
Magnetic resonance imaging of blood vessels at high fields: In vivo and in vitro measurements and image simulation, Magnetic Resonance in Medicine, 16(1), pp9–18, October 1990
They both predate the PNAS papers by a couple of years. I don't have access to the Huettel text - does it include references to these two papers? In a very (too) fast skim of the Kwong paper I didn't notice any references to earlier BOLD work by the MGH group GyroMagician (talk) 20:46, 14 March 2012 (UTC)
Ah, I missed one:
Brain magnetic resonance imaging with contrast dependent on blood oxygenation, PNAS, 87(24) pp9868-9872, December 1, 1990
GyroMagician (talk) 20:55, 14 March 2012 (UTC)


I believed the argument here is who is the first group performing BOLD fMRI in human. Without doubts, BOLD was discovered by Dr. Ogawa on 1990 and fMRI was performed in human by Dr. Belliveau on 1989. However, these three groups, Dr. Bandettini, Dr. Kwong (same as Dr. Belliveau), and Dr. Ogawa investigated independently and published the result of their BOLD fMRI in human almost at the same time. I have Dr. Huettel and Dr. Song's book. They indeed stated what the anonymous said. but, this is just single source. I can provided enormous among of source simultaneously citing these groups for the discovery of BOLD fMRI and none of them saying that Dr. Ogawa is replicating Dr. Kwong's work. Few examples from the fMRI textbooks: Roberto Cabeza, Handbook of Functional Neuroimaging of Cognition, 2001, p.29; Richard Buxton, Introduction to functional magnetic resonance imaging, 2009, p.118; Scott Faro, BOLD fMRI, 2010, p.13; Peter Jezzard, Functional MRI, 2001, p125; Stephan Ulmer,fMRI Basics and Clinical Applications, 2010, p.52; Nicole Lazar, The Statistical Analysis of Functional MRI Data, 2008, p.14 One more evidence, the Wikipedia entry of Kenneth Kwong clearly said that "Most researchers credit Kwong and Ogawa independently with the discovery of what is now called, Functional MRI (fMRI)." cecilyen —Preceding undated comment added 23:12, 18 March 2012 (UTC).

Second image

The second image: "FMRI image of the brain of a participant in the Personal Genome Project." looks a lot like an MRI, rather than an fMRI. Does anyone have an argument for keeping this? I think it could provoke confusion. Freeranging intellect (talk) 16:47, 1 November 2013 (UTC)

It's difficult to say without seeing the scan parameters, but I'd guess this is an un-processed fMRI run. After all, that's just an MR sequence, right? You don't get blobs until it's processed. GyroMagician (talk) 16:06, 2 November 2013 (UTC)

Potential merge into this article of 'Spinal fMRI'

I saw Spinal fMRI on the 'dusty articles' list as an article that hasn't been updated in several years, and it looks like it substantially overlaps with this one. I don't know enough about medical imaging to know for sure, so haven't added the formal merge tags. Could other editors weigh in on whether this merge seems reasonable?Dialectric (talk) 12:50, 20 February 2015 (UTC)

I think I would probably be against that. Spinal fMRI is such a little-used technique that even a single sentence in this article would verge on WP:UNDUE. I don't see any serious problem with keeping the current article as is -- it's not very good, but good enough to be useful. Looie496 (talk) 15:29, 20 February 2015 (UTC)

In animals and Reducing Length

I moved the section on animal subjects from "Combining with other methods" to it's own section, since it's not really another method (although I know fMRI in mice requires an injection of a contrast solution). It might make sense to delete the whole thing though. However, it also might make sense to find chunks that would be better placed in their own articles. For example, fMRI analysis is a hugely complicated topic and probably merits it's own entry. Then we could give a good summary and add a "see also" at the top, without sacrificing important details. Xttina.Garnet (talk) 13:08, 29 April 2015 (UTC)

External links modified (January 2018)

Hello fellow Wikipedians,

I have just modified 5 external links on Functional magnetic resonance imaging. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}} (last update: 18 January 2022).

  • If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
  • If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 22:09, 21 January 2018 (UTC)

Retrieved from "https://en.wikipedia.org/w/index.php?title=Talk:Functional_magnetic_resonance_imaging/Archive_1&oldid=1136745518"