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The manipulation part is what fascinates me. They didn't just correlate alpha wave frequency with ownership perception. They used transcranial stimulation to artificially speed up or slow down the waves, and the subjective experience changed accordingly.

That's a pretty direct causal link between a measurable brain state and something as fundamental as "where does my body end?"

It also makes the self feel uncomfortably fragile
What they seem to have identified isn't "the limits of you" so much as a timing parameter the brain uses to decide whether two sensory streams belong together
I think this is still important. How do you define a system? By boundary of communication, where inside system communication is fast, communication with outside is slow and limited. Think ( ( ((CPU) Memory) ((GPU) memory) PC ) Internet ). Your PC is a hierarchy of systems split on boundaries of communication speed. So, it would be proper that a brain identifies what's "inside" the brain in similar way.

So, ping>1 = that part is outside.

This was kind of my take too. It was like speeding up or delaying the refresh rate of the experience.
This is how these kinds of articles always go.
Original Paper: Parietal alpha frequency shapes own-body perception by modulating the temporal integration of bodily signals, https://www.nature.com/articles/s41467-025-67657-w

https://news.ki.se/how-brain-waves-shape-our-sense-of-self

> participants had a robotic arm tap the index finger of their real and fake hands, either at the exact same time or with a delay of up to 500 milliseconds between each tap. (...) Those with faster alpha waves appeared to rule out fake hands even with a tiny gap in taps, while those with slower waves were more likely to feel the fake hand as their own, even if the taps were farther apart.

That's the limit of "you"? Sounds more like a sampling rate/processing speed of the sense of touch.

FTA:

> With a third group of participants, they used a non-invasive technique called transcranial alternating current stimulation to speed up or slow down the frequency of a person's alpha waves. And sure enough, this seemed to correlate with how real a fake hand felt.

I know this is largely orthogonal to the article, and I know what “non-invasive” means and why it’s used in this sentence, but it made me chuckle - “this technique that changed the subject’s brain waves sufficient to literally impact their sense of self - but don’t worry! It’s non-invasive!”

It’s not an invasion, it’s just a “special operation”!
If invasive means using surgical tools to open up the skin and organs, then non-invasive means all things that don't require surgical tools.

OTH nearly all brain experiments are non-invasive. Did they mean to use the word to downplay how seriously impacting the experiment was?

“...it's not out of the question that you might have a very minor case of serious brain damage. But don't be alarmed all right...[it’s non-invasive]”
i guess putting your head in a microwave would also be considered "non-invasive" according to this logic. makes sense!
I wonder how those with multiple identities (DID), would affect this measurement. I know there are direct biomarkers in folk with it having to do with the frontal cortex and amygdala, and some neuroimaging being able to note vast differences in processing: https://pmc.ncbi.nlm.nih.gov/articles/PMC9045405/
I have DID and am also curious how it would affect the measurement. I'm just waking up so I've only skimmed the paper so far, but I suspect the results would differ depending on which of us was fronting.

We've noticed that each of us integrates not just sensory information differently, but we also seem to be "wired" differently.

For instance, we are AuDHD, and I, the primary host, lean strongly to the autism behavioral side, my co-host is somewhere between, and a secondary host leans strongly to the ADHD behavioral side. Things that are easy for me can be hard for another.

We also experience senses very differently. There have been many times where one of us can smell something strongly, switch, and the other can't smell it at all.

This affects other senses as well. When I watch a 24 fps movie at a theater, for about the first 10 minutes, all I see is a strobing of still images before I finally adapt and see motion. My co-host sees continuous motion right from the start. This may relate to the temporal binding window discussed in the paper as a motivation for their research.

Our working hypothesis since we were finally diagnosed has been that identity is, at least in part, an integration of both sensory information as well as how strongly various brain regions are activated by whichever identity or identities are most active at a particular time.

Lastly, we have the ability to "take control" over just part of the body. For example, for whatever reason, the motion of stirring a sauce is difficult to me, but it's trivial for another, so sometimes they'll take control of our arms to stir the pot while cooking. To me it feels like my arms have disappeared and someone else's arms are now attached and stirring the pot. This may be temporal binding window related because we do seem to experience sensory information at different speeds and this might cause us to get that alien hand feeling, which is sort of opposite of the rubber hand illusion.

So, I suspect that each of us would react differently to the rubber hand illusion test.

Some years ago I played a car game with Virtual Reality (VR). I noticed that it felt like the car was a part of me.

I wonder if the brain can experience if clothing, tools, bikes are part of the body?

Yes, I think it’s a well-known phenomenon that the brain extends its concept of the body to tools, vehicles etc that you learn to use well.
I actually think drivers routinely experience this, which explains a lot of road rage.
Yes. I think the concept you’re describing is proprioception:

https://en.wikipedia.org/wiki/Proprioception

A cell phone vibrating in your pocket: in the first days, after some days of use, many people would feel it vibrating as a muscle sensation, not as external thing vibrating.
Some overlap with ideas of Marshall McLuhan. Media as extensions of man.
So, how far does the human electric field extend outside the body? May be only picovolts or in that range... But can we measure that? Does the field exist past our skin?

Can things like meditation modify that? Or how about stuff like OOBE's like what some folks call astral projection? What do those practices to to the body's electric field?

It extends far enough for some use.

There are some capacitive sensors (Electric Potential Integrated Circuit or EPIC) that can work through clothing fabric (which is a resistor). Within a few millimeters they are good enough for a diagnostic EKG. It's also used for stress monitoring, and can be embedded in a mattress or seat back.

There are also magnetoencephalography, magnetocardiography, magnetogastrography, and magnetomyography systems in use, which use superconducting quantum interference devices (SQUID). Those are orders of magnitude sensitive enough (10^-18 T sensitivity vs 10^-6 T to 10^-9 T for some body processes or 10^-15 T for neural activity).

There is something like the heart field, about 3 to 4 feet according to the article.

https://pubmed.ncbi.nlm.nih.gov/20664147/

Meditation can alter a lot of “you” , and there is a reason you learn the advanced stuff under a guru (yoga mostly) or monk (buddhism).

>So, how far does the human electric field extend outside the body?

Electromagnetic fields extend infinitely.

>Can things like meditation modify that?

Anything you do with your brain changes the electric field. Reading this comment changed the electric field generated by your brain by some tiny amount.

Very interesting, and I suspect somewhat related to the phenomenon in high-performance sports and music where the player or athlete feels they have become one with the instrument or equipment. It happens after a certain level of expertise, and when everything is tuned just right, and often with the flow state.

The perception goes beyond feeling fine sensations in the interface to the instrument/equipment, but literally feeling like it is a part of your body. I've gotten it in both alpine ski racing and sportscar racing. When it is ON, moving a ski or wheel to a particular spot feels the same as when I'd put my foot on a particular rock where running in rough terrain, and often even more part of me than when kicking a soccer ball with my real foot. Both the sensitivity of the feel (feedback) and the precision with which I could execute was just an entire other level, and it is still weird to think of how it was often better feedback & precision than my own foot in a less-skilled situation.

I wonder if this can be used to cure or alleviate phantom pain in amputees.
More likely it will be used to brain control the population
"The researchers say that the findings could lead to new understanding of or treatments for conditions where the brain's body maps have gone askew, such as schizophrenia or the sensation of 'phantom limbs' experienced by amputees."
I wonder if having a feel for musical timing works similarly where a brain wave frequency determines how 'thight' your sense of timing is. Would be sick if you could improve that aspect of musicality with stimulation
I do wonder how far they would get with the phantom limb stuff. We know phantom limb stuff is encoded before birth so would alpha waves adjust something so fundamential?
Wow, that’s really interesting! It seems like alpha waves are the ‘tick rate’ of this system, and some set number of ticks are required to update the body model?
I suggest you all to read The Rhythms of the Brain, a free book as a paper in PDF form.

https://duckduckgo.com/l/?uddg=https%3A%2F%2Fneurophysics.uc...

So maybe tin foil hats can be useful after all?
In college I tried to participate in a rubber-hand-illusion while wearing an EEG, but the stimulation was done by the researcher manually and I never felt the illusion. This does show an interesting twist, using a robot arm for repeated and accurate stimulation.
The idea of "ownership of a body" made me think about a quote I heard a long time ago, while talking amongst musicians while waiting to get up and perform. It felt like some secret knowledge that I gained privilege to, while somewhat inebriated and it hasn't left me since.

> I _have_ a body, I _am_ a soul.

Maybe what they're identifying is the first half of that statement, how we interpret the former, through the presence of the latter.

This is interesting but i find it strange than there is no tests with a controls groups with closed eyes. Maybe some of the observed effects are visual only or psychological and not tactile at all.
I think, this experiment was earlier described in Ramachandran's 1998 book Phantoms in the Brain: Probing the Mysteries of the Human Mind
Could possibly be applied to enhance performance in sports.

You always hear about how something is an extension of the body to the best athletes.

although our internet is whitelist-blocked and I can only read the comments here, this reminds me of something my friend said some years ago, he said my car is the extension of my limbs and I can feel the limits of my car similar to my hands and feet
Wasn’t this phenomenon already described by VS Ramachandran in his book Phantoms in the Brain?
This has me thinking of Pluribus
I don't exist and that's okay
Interesting.

Now run the same kinds of tests while listening to music, meditation, sleep, orgasm, psychoactive substances (including caffeine/alcohol/nicotine), during simulated stress event (hard slap in the face?), on different age groups, genders, races. Perhaps there are more than one version or definition of "You" that arises in certain circumstances.

I wonder what kind of physics hides in interactions between waves and neurons (I know it's a cursed topic).