Depends on what you mean by cognition, but as you yourself said, BOLD may be correlated with certain kinds of long(er)-term activity, and that in itself is very useful if interpreted carefully. No one claims to detect single "thoughts" or anything of the sort, at least I haven't seen anything so shameless.
Well, a lot of task fMRI designs are pretty shameless and clearly haven't taken the temporal resolution issues seriously, at least when it comes to interpreting their findings in discussions (i.e. claiming that certain regions being involved must mean certain kind of cognition, e.g. "thoughts" must be involved too). And there have definitely been a few papers trying to show they can e.g. reconstruct the image ("thought") in a person's mind from the fMRI signal.
But I don't think we are really disagreeing on anything major here. I do think there is likely some useful potential locked away in carefully designed resting-state fMRI studies, probably especially for certain chronic and/or persistent systemic cognitive things like e.g. ADHD, autism, or, perhaps more fruitfully, it might just help with more basic understanding of things like sleep. But, I also won't be holding my breath for anything major coming out of fMRI anytime soon.
It is especially unforgiveable that the title of on the news release itself is about "40 percent of MRI signals". What, as in all MRI, not just fMRI? Hopefully an honest typo and not just resulting from ignorance.
Dr. Mike, a rare YouTube doctor who is not peddling supplements and wares, and thus seems to be at the forefront of medical critical thinking on the platform, interviewed Dr. Amen recently[0]. I haven't finished the interview yet, but having watched some others, generally the approach is to let the interviewee make their grandiose claims, agree with whatever vague generalities and truisms they use in their rhetoric (yes it's true, doctors don't spend enough time explaining things to patients!), and then lay into them on the actual science and evidence.
Dr. Mike did an incredible job in that interview. He gave Dr. Amen all the rope to hang himself with his own words. When you're hawking a diagnosis method and you're not interested in building up the foundation of evidence for it by doing a double blinded, randomized controlled study. And that the results of said study would change how your treating patients it's pretty clear who the snake oil salesman is
I also thought the rest of the interview was really worthwhile - they talked a lot about real problems in the medical industry from different perspectives. What a great and critical discussion from Dr. Mike. If Amen had conceded the point they could have moved on. There could be real findings to be had there, and some may even match his conclusions, but many likely will not, and the whole thing could also be pure fiction. We should want better answers to these questions. It's unfortunate to watch someone as seemingly intelligent and well-informed as Amen come across as shilling snake oil, and/or just being hung up on his ego, at the end of it all. Scientific literacy is so critical, because it's easy to cloak pseudoscience behind high-tech smokescreens.
Unfortunately I worry about the rebound effect, where even though the entire interview was debunking his claims this could still on average increase amen’s popularity.
I worry about the same effect. Debunking style conversations produce the opposite effect in viewers who instinctively take the side of anyone who appears to be trying to help and reactively take the opposite position of anyone who appears to be attacking.
So many will watch this video and come away siding with Dr. Amen, feeling like they're doing the right thing to disregard the mean man on the other side who is questioning everything.
The alternative medicine and pseudoscience communities thrive on "but what if it works" or "they're just trying to help" attitudes, which snake oil sellers capitalize on.
I'm no expert in medicine, but I watched that entire video and your analogy about performance and rope doesn't fit well with how it came across to me.
I actually thought the interviewer was a little disingenuous. He said things like "We're on the same team" and "I'm not trying to trap you", then proceeded to lob his guest with criticisms from the other team and questions aimed to maneuver him into a contradiction. There's nothing inherently wrong with that, but if you're going to do it, be forthright you're engaging in a debate.
Earlier in the interview he could have put his cards on the table and plainly stated "Myself and others in the medical community are skeptical of the efficacy of imaging on outcomes, and a rigorous, double-blind study would lend dramatic support for us to adopt what you're touting."
Then they could have had the conversation he was clearly after, focused on that issue.
Instead it felt like I was watching for ages as he took a winding route to get there, then the interview cut off abruptly when they finally really did.
The overlays applied in editing while helpful and fair in some cases, at other times came across as one-sided. It's a shame we can't see a follow-up where the interviewee has an opportunity to respond (or squirm) in light of them.
For the record I would very much love to see additional research and gold-standard, double-blind studies. In the meantime I'll treat this as "Hey, we've got this interesting thing we can measure, we're seeing some good results in our practice" without over-emphasizing the confidence in this one diagnostic.
I did find the bit interesting about how having a gauge you can viscerally see impacted patients' engagement in care. Both agreed on the potential usefulness of that aspect, and conceded the difference in profiles between patients coming to Dr. Amen vs. ordinary front-line family physicians.
In my opinion it's pretty clear dr. Amen was really only there to push a book. He was never really interested in having a real discussion anyway, hes just shilling. If you're going to be pushing a diagnostic method and supplements to solve issues without any proof whatsoever that's a problem. No one should be making statements about the efficacy of a technique without evidence. The fact that he got defensive about it speaks volumes about his character and what he hopes to get away with.
I'm not sure why you are drawing a parallel to a good doctor that smokes.
I never said "Doctor Mike" is a bad doctor. I have no idea if he is a good or bad doctor.
Further, an ad hominem is when a person attacks someone's character without any base.
I wrote specifically about him not being at the forefront and questioning his values, as displayed by his actions during the pandemic. His actions were literally not in line with Covid guidelines. Those are guidelines that were formulated by hundreds (thousands?) of doctors, all of whom sought to be at the forefront of medical science during a pandemic.
As another user said, MRI scans not corresponding to brain activity is not really news, and in at least the part of the US I live in, MRI scans are not so easily recommended, especially since they're not covered by health insurance.
Dr. Amen should be called out, of course, but it doesn't mean a doctor is at the forefront for doing so.
> Further, an ad hominem is when a person attacks someone's character without any base.
An Ad-Hominem is specifically an attack on someone's arguments using some un-related attack on their character.
EG: "Dr. John's Opinions about vaccines are invalid because he smokes cigarettes." or "James assertion that the earth is round is invalid because he thinks that dogs are better than cats."
Ad-Hom is short for argumentum ad hominem. If you aren't making an argument with your attack, you are just insulting someone.
> I'm not sure why you are drawing a parallel to a good doctor that smokes.
Presumably because it is very analogous. You are essentially saying Dr. Mike shouldn’t be trusted because he made a bad decision. That is extremely similar to saying you shouldn’t trust a doctor’s advice because they happen to smoke.
> Further, an ad hominem is when a person attacks someone's character without any base.
No. An ad hominem is when the person is attacked rather than the argument. A terrible person can still make a perfectly sound argument. Calling them terrible doesn’t change the argument, even if it is emotionally satisfying.
> I wrote specifically about him not being at the forefront and questioning his values, as displayed by his actions during the pandemic.
You’re attacking his actions and not his recommendations. Ad hominem.
smoking is not an appropriate analogy at least insofar it is primarily damaging to the individual (claims of second hand smoke aside), whereas exposing oneself during covid is more broadly damaging as the purpose of social distancing was specifically to avoid spreading the disease, not to oneself, but to more vulnerable individuals. moreover it can be indicative that he is self-interested, that is, by acting hypocritically, while not in and of itself evidence, is consistent with 'charlatan behavior' as is, i would add, interviewing a known charlatan dr aman. aman detractors will think he is 'being shown' but the reality is that aman or similar wins legitimacy, which the interviewer knows, since his aim is entertainment, not medicine, in his capacity as an interviewer.
it is not ad-hominem to try to understand a person's motivations for expressing a particular opinion, which is why the above poster referred to 'character' which is not specific to the definition of ad-hominem, but is in the spirit thereof, that is, distracting from the argument. but if the person has shown themselves to be working contradictorily to public health policy, especially in consideration of the hippocratic oath, you may ask reasonably what they are about.
> smoking is not an appropriate analogy at least insofar
Missing the forest for the trees.
The point isn’t that neglecting to mask is exactly the same as smoking. Obviously these are different. The point is that in both cases the person in question is advising one thing and doing another. The fact that a doctor smokes or doesn’t mask up in a pandemic does not mean that their advice to not smoke or to wear a mask is not good advice.
If a person regularly snacks on lead paint but tells you not to eat paint, the advice is still good even if it’s coming from an idiot.
> it is not ad-hominem to try to understand a person's motivations
Sure, but claims of hypocrisy are still not a rebuttal.
No doubt it was hypocritical for Dr Mike to tell others to social distance and then hop on a boat with a dozen people unmasked, just as it was hypocritical for Gavin Newsom to attend a dinner at The French Laundry while telling others to stay home.
This isn’t actually relevant to whether the advice to socially distance was sound, though.
Yet here you are trying to convince folks why this doesn't lead to poor morals, low self-awareness, and a lack of trust in doctors. We are talking about a doctor, of course, not just an average nobody. And we are talking about a doctor with 6 million subscribers. His influence is wide.
Last I checked, a doctor is not the same as a politician.
Do you have a point except to cast this guy as untrustworthy because he did one stupid thing that got photographed half a decade ago? I feel like the pedantry about what ad hominem means and arguments about analogies and now references to morality and politicians is distracting from whatever your core point is.
> lack of trust in doctors
I don’t think demanding perfection from doctors helps with trust either.
This study is validating a commonplace fMRI measure (change in blood-oxygenation-level-dependent or BOLD signal) by comparing it with a different MRI technique, one that uses a multiparametric quantitative BOLD model, a different model for BOLD derived from two separate MRI scans which measure two different kinds of signal (transverse relaxation rates), and then multiply/divide by a bunch of constants to get at a value.
I'm a software engineer in this field, and this is my layman-learns-a-bit-of-shop-talk understanding of it. Both of these techniques involve multiple layers of statistical assumptions, and multiple steps of "analysing" data, which in itself involves implicit assumptions, rules of thumb and other steps that have never sat well with me. A very basic example of this kind of multi-step data massaging is "does this signal look a bit rough? No worries, let's Gaussian-filter it".
A lot of my skepticism is due to ignorance, no doubt, and I'd probably be braver in making general claims from the image I get in the end if I was more educated in the actual biophysics of it. But my main point is that it is not at all obvious that you can simply claim "signal B shows that signal A doesn't correspond to actual brain activity", when it is quite arguable whether signal B really does measure the ground truth, or whether it is simply prone to different modelling errors.
In the paper itself, the authors say that it is limited by methodology, but because they don't have the device to get an independent measure of brain activation, they use quantitative MRI. They also say it's because of radiation exposure and blah blah, but the real reason is their uni can't afford a PET scanner for them to use.
"The gold standard for CBF and CMRO2 measurements is 15O PET; but this technique requires an on-site cyclotron, a sophisticated imaging setup and substantial experience in handling three different radiotracers (CBF, 15O-water; CBV, 15O-CO; OEF, 15O-gas) of short half-lives8,35. Furthermore, this invasive method poses certain risks to participants owing to the exposure to radioactivity and arterial sampling."
This is why I love this site. You get input from so many specialized folks! I appreciate you contributing your expertise and I also appreciate you calling out the limits to that knowledge.
Two points I'm hoping you can help clarify:
> Researchers ... found that an increased fMRI signal is associated with reduced brain activity in around 40 percent of cases.
So it's not just that they found it was uncorrelated, they found it was anticorrelated in 40% of cases?
And you are suggesting that conclusion suffers from the same potential issues as these fMRI studies in general?
Like you mention, it seems to me if we wanted to really validate the model, we'd have to run the same experiment with two, three, or maybe even more different modalities (fMRI, PET with different tracers, etc).
If you have a PET/MR system [0], you can probably do this "gold standard" comparison, and I know that one is used for research studies. I think you can piggy-back off a different study's healthy controls to write a paper like this, if that study already uses PET/MR and if adding an oxygen metabolite scan isn't a big problem. But that's speaking as someone who does not design experiments.
Curious what you find to be "bs" about the results of this paper? That statistical corrections are necessary when analysing fMRI scans to prevent spurious "activations" that are only there by chance?
It's not that fMRI itself is controversial, it's that it is prone to statistical abuse unless you're careful in how you analyse the data. That's what the dead salmon study showed - some voxels will appear "active" purely by statistical chance, so without correction you will get spurious activations.
This study questions the fMRI method itself, not the statistical analysis (you're right that the dead salmon study was challenging the way statistical analysis is done). Basically, this study claims that the association between the BOLD signal measured by fMRI and actual brain activity is quite weak, and they are even anti-correlated in 40% of cases.
There is no statistical analysis that can save you if your interpretation of a signal is wrong (for example, you can't get information about personality from phrenology, regardless of what statistical analysis you try to apply to the data). That's not to say that we need to just trust this study implicitly - I'm just trying to describe how serious of a problem to the field their claim is.
I agree, except with the word "slightly". It can be so significant that this increased cost/friction is the very mechanism of the sanctions' effectiveness. Is it possible to police the Russian oil shadow fleet to extinction? Maybe, but even without doing so you can impose a decent haircut on their profits by issuing scary-sounding press releases and leaving it at that.
Increased costs might be a factor in a competing commercial market, but for military purposes, you buy the components no matter the price or search for an alternative (China is now making lot of components - for example, resistors, transistors, logic chips - I have several 74HC chips of Chinese origin, and they are very cheap). Also, there are thousands ships and no legal basis for "policing" them in open sea.
Attention economy, the algorithm, rage-bait, maximizing engagement, doomscrolling - pick your buzzword. Individual people care about all sorts of weird things, but on average, this and no other reason is why a person in Idaho suddenly finds themselves caring about Manhattan congestion pricing. It's easy to point a finger and laugh/marvel when it's something so obviously absurd to you, but of course you and I both have entirely different blind spots where our attention is marshalled and our opinion is formed by the rage-bait engine. Ours must seem preposterous to those on the outside looking in, too.
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