Reading Minds with Ultrasound: A Less-Invasive Technique to Decode the Brain | Hacker News Reader

Reading Minds with Ultrasound: A Less-Invasive Technique to Decode the Brain

caltech.edu

The nerd in me finds brain interface research super-exciting and even participated in studies in the past. The human is scared shitless at times. What if these things eventually work? I cannot imagine a world in which "mind reading" is not going to be terribly abused (and I am a rather nice and reasonable guy in general).

And the things that scare me are just the few things that we can easily reason about already, not even the things that we do not yet know being possible with it. Surveillance states turned up to eleven, psychological violence up to eleven, interrogation, torture, ethically challenged tech bros going full-Zck on people's minds. Could maybe one mind invade another brain and use it to enhance its capabilities (suppressing the mind that resided there so far)? A few brains interacting so closely that they create an a lot more intelligent thing - outpacing everyone who is not willing to subject themself to that (what would that do to society?)? What happens when the interface fails biologically (for invasive methods of interfacing), like developing inflammation, bleedings, scar tissue? Technically failures like the interface device dying, broken or unreliable connections or even just batteries running low? Before you dismiss the latter, imagine how you feel when you involuntarily cannot use your phone and scale that up by a lot - as you would not be losing a tool but a part of yourself.

Enough anxiety about the future for now - have a nice day instead ;)

I like Kevin Kelly's point of view, which he talked about recently on David Perell's podcast:

"When the first humanoid picked up a rock and turned it into a hammer, either to make a shelter or to kill his brother, he suddenly had a new choice he never had before. That choice is good. You see what I’m saying? Even the choice to do evil is itself a good. Which means that if there’s a 50/50 wash between good and evil, the fact that there’s another choice gives it a 1% edge.

So there’s 51% versus 49%. So that’s why I say that given everything, even the choices to do evil are a good, that we have 51% good and 49% bad. That 1 or 2% Delta, the tiny, tiny little bit better, the incremental creep of goodness and betterment compounded yearly is civilization. All we need is to have 1% better. What we need to do is create 1% more than we destroy. Then we have civilization. And by the way, 1% it’s almost invisible. Look around the world and say, half of it’s crap. Yes, it’s true. There’s only a 1% tiny bit, but that 1% difference, that little tiny bit, is all that we need. And that little tiny bit comes from, even the evil choices are choices and those choices are good. It’s good to have a choice."

Kevin Kelly

Or alternatively the ability to control minds reduces the number of choices you do good as it consolidated power in fewer people. Therefore under your model it increases evil.

This is assuming you're the hominid making the choice and not the hominid to whom to the choice is applied.

I agree. Imagine having your senses overwhelmed by images and sensations of the most terrifying shit you can’t even imagine. And the way governments excuse their repeated attacks on encryption - no safe harbour - who can’t see that directly translating to mind reading?

A scifi author wrote about "the mechanism" where just formulating a bit too clear intent against another person resulted in disabling pain and multiple infractions would result in reprogramming.

Now, that same mechanism would prevent most actions that could initiate said intent too.

In the stories, this is not abused, and serves humanity reasonably well.

We are so damn far from any sort of state where things like this make sense. They can, will be abused.

I experience the same emotions. The opportunity to share experience more directly is super compelling!

But yeah. Major league downsides.

Spoiler: the ultrasound is less invasive than implanting electrodes in the brain, but still requires removing a piece of the skull.

It can be used through the skull, there are people doing that already, it just doesn’t deliver as high of resolution yet.

I was under the naive impression that the acoustic impedance mismatch across the skull/cranial-fluid/brain means that not enough ultrasound would go through for useful imaging. Is that not as big a deal, or is the problems somehow circumvented?

EDIT: Here’s what the article says about this:

> "Current high-resolution brain–machine interfaces use electrode arrays that require brain surgery, which includes opening the dura, the strong fibrous membrane between the skull and the brain, and implanting the electrodes directly into the brain. But ultrasound signals can pass through the dura and brain non-invasively. Only a small, ultrasound-transparent window needs to be implanted in the skull; this surgery is significantly less invasive than that required for implanting electrodes," says Andersen.

> Though this research was carried out in non-human primates, a collaboration is in the works with Dr. Charles Liu, a neurosurgeon at USC, to study the technology with human volunteers who, because of traumatic brain injuries, have had a piece of skull removed. Because ultrasound waves can pass unaffected through these "acoustic windows," it will be possible to study how well functional ultrasound can measure and decode brain activity in these individuals.

Can you link to this research? I was under the impression that bone acts pretty much like a backstop when imaging with ultrasound arrays?

The links are to 6 patents and talks by Mary Lou Jepsen. She won't publish scientific papers until everything is protected by patents.

[1] https://www.openwater.cc/technology

[2] https://www.openwater.cc/events

Thanks for sharing. It will be interesting to read the paper, usually when you see exactly what they did the sheen comes off considerably. From what I understand, it's basically taking advantage of the doppler effect in the microvasculature to estimate brain activity? I guess the concept is nothing new (ultra sound has long taken advantage of doppler shift), it's more that they've found a way to get some images apparently with a spatial resolution that is sufficient enough to be used for "mind reading".

I did some similar experiments in my old job, but we used fMRI in the human visual cortex instead of ultrasound. We found that even when we imaged at surprisingly low resolutions (where the microvasculature couldn't be imaged) there was a still a lot of data which when we threw into a machine learning model could be used to predictably estimate the visual stimuli the person had seen during a basic task. In case you aren't aware, fMRI is actually measuring the oxygenation of the blood (not actually brain activity, we simply infer that areas with high oxygenation are highly active - which is an argument for another day!), and we theorised that the reason we could still decode information at low resolution was because of large gross veins distributed across the brain. If you imagine that when shown two stimuli A and B, the brain has two distinct patterns of activity A and B, the blood flow in those two cases will be slightly different and this will be reflected even in the gross veins, and we believed our machine learning model was able to see those difference in the gross veins and using those to "mind read".

I would definitely want to look at the study more carefully, to see what the investigators have done to remove the possibility that there are gross activity pattern changes that their learning model (I am sure they're using one) might actually be using to "mind read". It will also be interesting to see how the model is built and what they are doing to reliably clean up the data.

I also wonder how much it might heat up the brain? And whether that would be a problem for sustained use? (In practice this heating effect is occasionally limiting for some other forms of ultrasound (e.g. TEE) requiring you to take a break or reduce the power.)

This is pretty well studied now. There are safe ranges and durations, but yeah ultrasound at high frequencies is used for brain surgery today so it’s a delicate tool. It’s also lacking large scale human studies currently.

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