FR version is available. Content is displayed in original English for accuracy.
Advertisement
Advertisement
⚡ Community Insights
Discussion Sentiment
73% Positive
Analyzed from 1187 words in the discussion.
Trending Topics
#bubbles#brain#ultrasound#sparse#imaging#resolution#contrast#technique#more#blood
Discussion (23 Comments)Read Original on HackerNews
If I bring my pet mouse to the cinema and my friend scans the movie back using his apple ifmri does the DRM still holds or will the mouses be DRM locked? Will my iris suffice for booting my computer or would I need to press accept all brainwave cookies? Can I email my local Flock representative to install a new Brain Pole in my neighborhood? I saw a bunch of dark thoughted young males around and my amazon think camera says the probability of missing packages increased.
[0]https://ai.meta.com/blog/tribe-v2-brain-predictive-foundatio...
All of these imaging techniques are very involved. Ultrasound requires direct contact and this technique only works with a long IV infusion of bubbles. fMRI isn’t going to be a portable device that you can point at something for many reasons.
The connection to what you’re thinking is more sci-fi than reality. This technique could theoretically see some changes in blood flow to different regions, but what would that mean? Is the patient having anxiety, or are they just nervous about the IV injecting bubbles into them to travel to their brain and the machine attached to their head?
I wonder what Orwell would have thought.
The super-resolution trick as they’ve done it is highly reliant on the sparseness of the bubbles. If you imagine a point or a very sparse set of points at low resolution, you can fit for the locations of those points even though you don’t see them clearly. This is a common technique in radio astronomy and (I assume although I don’t have personal knowledge) astrometry, and compressed sensing was an extremely hot field a while back.
But RBCs are weird squishy things, and they fill the bloodstream quite densely, and ChatGPT estimates that they’re spaced about 20µm apart and that, when confined to a capillary, they’re about 7µm long. (And that sounds at least plausibly correct to me.)
So, even ignoring the much worse scattering properties of RBCs, they not nearly as sparse. You mostly lose a whole dimension of sparseness and up trying to resolve the entire capillary. Which seems possible but much harder. Unfortunately, brain capillaries are about 40µm apart, so the result might be a mess.
The article did not say what wavelength they’re using or what their native (wavelength/2) resolution is.
I’m filing this in the category of technologies I wish could be true, but for which no plausible path to overcoming the obvious limitations has been provided.
My assumptions here are *extremely generous*, i.e. favorable to the "oh, we'll just make it work with natural contrast", and even then, they can't hand wave 5-6 orders of magnitude of improvement. Furthermore, because of the use of super resolution, I'm guessing there's some exponential factor in there, i.e. double the density of bubbles/tracking points past some critical limit, then you need 8x the data to reconstruct things.
The high resolution images were generated by injecting sparse bubbles of this contrast agent. How sparse are they? Is the image we see a stacked set of many bubbles over time composited together?
Their aspirations at the end of doing this without the bubbles are great, but there’s a big “now draw the rest of the owl” energy around that leap. The first technique relies entirely on the bubbles, but they provide no explanation for how they think this could be achievable without the bubbles other than vaguely saying that technology is advancing.
They used a trick to inject sparse bubbles into the patient and let them flow through the brain, then looked for the perturbations caused by those sparse bubbles.
The Midjourney scanners aren’t injecting this bubble contrast agent into everyone’s veins.
Happy to be corrected. But if that's right then this... does the BS thing in a potentially less intrusive way?
> The bubbles themselves are pockets of sulfur hexafluoride encapsulated in lipid shells. They're an FDA-approved contrast agent,
Combined with ultrasound, could these be causing damage of any kind to the vasculature?
> A few years ago, a paper came out that blew our minds. The idea was that you can decode what someone is looking at just from their brain activity.
How realistically close can this get to reading thoughts, visuals, etc.?
Do we have a path to imaging people's visual cortex? Their inner lives, dialogues, memories? (Scary thought - this could be used as an interrogation tool without consent. "Did you kill Bob?" could be a simple brain scan.)
Can it be done in real time in a feedback loop and perhaps be used as an advanced reinforcement learning system?
That's bad enough in democracies, but the consequences in more common forms of government seem really dystopian.
I really don't understand why a fetus' heart can be examined for defects, but you can't use it in the office to tell me if my labrum is torn?
But high resolution imaging of blood flow? That's a pretty great medical diagnostic tool if you can make it more available and cheaper.
Edit: wow, serves me right for asking / not understanding that contrast means SF6...