Functional ultrasound through the skull
brainhack.vercel.app
brainhack.vercel.app
Now you can tell exactly what is going on and the person is thinking! Specifically it'll be either: (1) "oh my god, I have an ice pick in my brain" or (2) nothing, because they have an ice pick in their brain.
Apparently if you're really good, you can actually find the part of the brain that has to do with addiction and zap it.
They use ultrasound after getting it to work with a metal probe.
It wouldn't be the first time ice picks have been used inside the brain. In answering a question [1] on what the difference is in medicine between an -ectomy, an -ostomy, and an -otomy in The Straight Dope we find this:
> • Finally, there’s “-otomy,” (or “-tomy”), which means to slice it up, i.e., an operation in which cutting is involved. Thus we can distinguish a lobectomy, in which a lobe, typically of the brain, is removed, from a lobotomy, in which they merely jab an ice pick in there and chop things up.
> I’m not kidding, either. You might want to read an engrossing volume entitled Great and Desperate Cures: The Rise and Decline of Psychosurgery and Other Radical Treatments for Mental Illness, by Elliott Valenstein (1986). Valenstein quotes a letter written in the mid-1940s by one prominent lobotomist, Walter Freeman:
>> I have also been trying out a sort of half-way stage between electroshock and prefrontal lobotomy [to treat mental patients]. … This consists of knocking them out with a shock and while they are under the ‘anesthetic’ thrusting an ice pick up between the eyeball and the eyelid through the roof of the orbit [the bony cavity that contains the eye] actually into the frontal lobe of the brain and making the lateral cut by swinging the thing from side to side. I have done two patients on both sides and another on one side without running into any complications, except a very black eye in one case. There may be trouble later on but it seemed fairly easy, although definitely a disagreeable thing to watch. It remains to be seen how these cases hold up, but so far they have shown considerable relief of their symptoms, and only some of the minor behavior difficulties that follow lobotomy. [That is, prefrontal lobotomy, which typically involved boring holes through the front of the skull. The ice pick operation is called a transorbital lobotomy.] They can even get up and go home within an hour or so. If this works out it will be a great advance for people who are too bad for shock but not bad enough for surgery.
> Freeman went around the country in the late 1940s demonstrating this technique in mental hospitals. These exhibitions reportedly went well for the most part, except on those occasions when the patient bled too much or the ice pick broke off within the orbit or inside the skull. To remedy this problem, the ice pick was later replaced with a sturdier instrument and an ordinary carpenter’s hammer was used to drive it into the brain.
> The first lobotomy in the United States took place on September 14, 1936. By August 15, 1949, the procedure had been performed 10,706 times. In the mid-1950s the popularity of the operation waned due to the availability of psychotropic drugs, which offered similar benefits without the trauma. One hopes today the practice is extinct, but you never know.
[1] https://www.straightdope.com/21341781/in-medicine-what-s-the...
This is an A+
But where did the 22 dB/cm/MHz attenuation number come from? We were skeptical…”
Not just no note of background checks, but no note of restrictions of any kind.
There are many words about international shipping and related restrictions. But no “you need to be a doctor” as far as I see anywhere.
This is either a “reddit being reddit” situation, or skulls unlimited had a change in their policies in the past.
Part 2 has an interview with a law professor that specializes in death and what happens after people die. Fascinating!
Focused ultrasound is already used for non-invasive neuromodulation. Raag Airan's lab at Stanford does this for example using ultrasound uncaging.
https://www.frontiersin.org/journals/neuroscience/articles/1...
https://www.sciencedirect.com/science/article/pii/S089662731...
Also see the work by Urvi Vyas, eg
https://pubmed.ncbi.nlm.nih.gov/27587047/
I don't mean to discount the cool imaging-related reconstruction of a point spread function, but rather to say that ultrasound attenuation through the skull an soft tissue has already been well characterized and it's not a surprise that it is viable to pass through.
The method we’re proposing would have mm resolution.
The fontanelles enable good ultrasound imaging on an entirely different level. A highres greyscale image vs a few sparse blobs of doppler from major vessels.
OpenwaterHealth/opw_neuromod_sw: https://github.com/OpenwaterHealth/opw_neuromod_sw :
> OpenWater's Transcranial Focused Ultrasound Platform. open-LIFU is an ultrasound platform designed to help researchers transmit focused ultrasound beams into subject’s brains, so that those researchers can learn more about how different types of ultrasound beams interact with the neurons in the brain. Unlike other focused ultrasound systems which are aimed only by their placement on the head, open-LIFU uses an array to precisely steer the ultrasound focus to the target location, while its wearable small size allows transmission through the forehead into a precise spot location in the brain even while the patient is moving.
FWIU NIRS is sufficient for most nontherepeautic diagnostics though. (Non-optogenetically, infrared light stimulates neuronal growth, and blue and green lights inhibit neuronal growth)
They are planning to locally change the electrical conductivity of brain tissue by focused ultrasound, modulate that with at few hundred kHz and do a lock-in (EEG) measurement to deduce electrical activity at that spot on the scale of 1mm. Pretty wild if that actually works.
Is it fair to say that their claims about spatial resolution being >>> existing EEG options are jumping the gun? If I understand correctly, you need to be targeting individual 1mm^2 regions with individual acoustic lenses, which means 17,000 channels would required 17,000 separate, uniquely-tuned ultrasound emitters, yes? Even if that's possible without messing up the data (the MHz range is big, but is it that big?) it seems like a trivial impossibility to fit that in one headset -- even the standard 32-64 EEG channels alone seem like a long shot. But maybe I'm overly cynical, or one emitter could be used to usefully excite multiple regions at once?
Another oddity in that paper is that it reads like we're trying to find persistent signals in the brain, like a needle in a haystack, whereas my understanding was that the field is moving decisively towards tracking signal changes over time in a given region. Is my intuition correct that accounting for a moving target would add considerable complexity to this approach?
Either way, thanks for sharing the link. Definitely thought-provoking stuff...
> Is it fair to say that their claims about spatial resolution being >>> existing EEG options are jumping the gun? If I understand correctly, you need to be targeting individual 1mm^2 regions with individual acoustic lenses, which means 17,000 channels would required 17,000 separate, uniquely-tuned ultrasound emitters, yes? Even if that's possible without messing up the data (the MHz range is big, but is it that big?) it seems like a trivial impossibility to fit that in one headset -- even the standard 32-64 EEG channels alone seem like a long shot. But maybe I'm overly cynical, or one emitter could be used to usefully excite multiple regions at once?
Since the system is linear, you could use a single probe to focus at multiple spots. Each focus would be at a slightly different modulation frequency.
> Another oddity in that paper is that it reads like we're trying to find persistent signals in the brain, like a needle in a haystack, whereas my understanding was that the field is moving decisively towards tracking signal changes over time in a given region. Is my intuition correct that accounting for a moving target would add considerable complexity to this approach?
This method would indeed let you track signals that change over time. Lock-in-amplifiers can output time-varying signals.
But that's a hard skill to develop.
"In physics, there's a word for 14 orders of magnitude of attenuation. It's called zero, i.e., you will measure nothing."
Lots of great sentences in here as noted in the other comments.
Even if you add noise to your simulation , when you go to the real world it will have lots of sources of noise and errors that you didn't model. In this case I suspect aligning the CT scan with the ultrasound probe will be extremely difficult.
Also there's a reason ultrasonographers are so highly paid, and it's mostly used for pregnancies. In normal tissue it kind of sucks as an imaging method. (On an absolute scale; obviously it's amazing technology.)
Eh maybe it will work though. You never know.
Pregnancies are a minority of ultrasound examinations.
https://www.researchgate.net/figure/Ultrasound-scan-types-Th...
But even according to that article, out of the 345 examinations only 102 were pregnancy scans, making them a minority of all scans made.
This was not cherry picked. It was the only one I could find. Feel free to provide better data since you were so sure...
> out of the 345 examinations only 102 were pregnancy scans, making them a minority of all scans made.
I knew you would say that. While this is mathematically that's clearly not what you were implying by saying it is a minority of scans.
I said "it's mostly used for pregnancies". The data supports that, not you.
It is exactly what I was saying. And I say this because I work in a hospital with several non-preggo ultrasound labs that are booked overtime. To achieve the same load of pregnancy scans the hospital would need to hire more OB-staff for scanning and the region would need a TFR of 25.
If anyone's interested I found those two paper really interesting:
- Aubry et al 2023[1], on potential risks and limitions of using focused ultrasound in the brain (tldr we don't know but have conservative estimates. Really interesting for me to see that HN article adding to that)
- Lord et al 2024[2], a first study on using Transcranial Focused Ultrasound to modulate the DMN and subjective experience
[1] https://arxiv.org/pdf/2311.05359
[2] https://www.researchgate.net/publication/381488518_Transcran...
It's done by the same people as the second paper I linked, on people attending a 10-day silent meditation retreat. My understanding so far is that the participants will be "zapped" a couple of time over the 10 days, to explore exactly what you describe ie alterations of consciousness similar to what's found in long term meditators on retreat, except induced on people who are already on retreat instead of people who'll have to go back to work afterwards.
I'll have more to report in a couple weeks time!
(If you'd like to share, I'm also curious as to what interests you in that field of study)
We've been developing slow-wave enhancement for the past 4 years using auditory stimulation.
The problem with using focused ultrasound to accomplish this (I believe), is that the focal point creates heat, and I don't believe we want to be consistently creating hot spots of neurons in the brain.
Other methods (acoustic, visual, haptic) have proven efficacy by "tricking" the brain into increasing slow-wave delta power, and tMCS (magnetic) coaxes the neurons into a slow-wave pattern - though this is not realistic outside of a clinical setting atm.
Absolutely there is tons happening in neuroscience (lots here in Sydney, Aus), and focused ultrasound has it's place, but as a daily use, I'm not there with it yet.
For treatment of depression, for diagnosis, etc, absolutely. Though in depression treatment, SAINT protocol tCMS is very impressive.
Sounds like a perfect way to find yourself dead with massive brain hemorrhage and someone jailed for unlicensed meme-medtech.
The big question for me is - how will it feel on a live person. Is it going to be painful? Could it alter/damage the brain tissue?
So basically - how safe is this tech?
Infant babies frequently have their brain scanned through the open fontanels.
If you turn the volume up to 11 you'll boil water with or can use it to machine steel but the energy levels in clinical practice is safe
They quote a book that the public at large (including me) can not check for the 22dB/cm/Mhz number.
The next best quote is the 8.3 dB/cm/Mhz quote. That article is available to the public:
https://pmc.ncbi.nlm.nih.gov/articles/PMC1560344/pdf/nihms94...
However I don't see any expression claiming a linear frequency dependence of attenuation up to 10 MHz.
> the number people will tell you in conversation.
Is very vague. Do your own research, find actual measurement data, don't extrapolate a few sub MHz measurements out to 10 Mhz, especially not if the error bars become ludicrously big.
Since I can't find the quoted frequency coefficient for attenuation I look at the possible candidates in that article: there's Figure 11, Table 1 and Table 3.
My gut feeling tells me they used table 3:
frequency in MHz | Longitudinal attenuation in Nepers per meter
0.272 | 14 +/- 17
0.548 | 53 +/- 43
0.840 | 70 +/- 28
I suspect they discarded the middle frequency because of the large error bar, so they are left with
Mhz | Np per m
0.272 | 14 +/- 17
0.840 | 70 +/- 28
the difference in frequency is 0.568 Mhz
so the difference in attenuation is then 56 +/- 45 Np per m. Yes the standard deviation is almost as large as the value. Let's see if we arrive close to their supposedly "quoted assumed linear frequency dependence of 8.3 dB / cm / Mhz "
2 x (56 Np per m) / ( 0.568 MHz x 100 cm per m x log(10) Np per 10 dB)
= 8.56 dB / cm / Mhz
close to their 8.3 "quote" which is really their own deduction, or whomever "derived" it in "conversation".
If you calculate the error bar: 8.56 +/- 6.88 dB / cm / MHz.
What they independently measured (props! actually good science):
11.18 dB / cm / MHz
Thats 2.62 / 6.88 = 0.38 standard deviations away. Thats not new science in the sense of hypothesis rejection, but a valuable extra datapoint refining the literature of values.
The likelihood of measuring a value 0.38 or more standard deviations away from the expected value would be: 70.4 % so not very surprising at all. Basically in conformance with the 8.56 +/- 6.88 dB / cm / MHz value.
https://www.mathportal.org/calculators/statistics-calculator...
I had went down a huge rabbit hole to find the source for the 22 dB/cm/MHz paper that everyone quoted. People reference the Diagnostic Ultrasound textbook; that textbook references an old nondigital ultrasound reference book, which finally references a Fry paper from 1977 [1].
It's funny because the Fry paper never explicitly mentions the number 22 dB/cm/MHz. But there was one figure (Figure 12), where if you fit a line through the data in that figure, you get a slope of 23.5 dB/cm/MHz.
Here's a spreadsheet of me fitting the data: https://docs.google.com/spreadsheets/d/1a70svm-zrzp1SQT5v2m_...
But yes, you're totally right that even the Fry paper Figure 12 was only up to 2 MHz, so it's totally not fair to extrapolate to 10 MHz.
I don't think there's enough rich pineal gland enthusiast to justify the cost, even if the system was truck mounted and mobile and thus hypothetically able to reach wider customer base.
But that'll still be expensive to develop, slow and still potentially lethal if done sufficiently wrong