> 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!”
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?"
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?
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.
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?
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?
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 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/
"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
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
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
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.
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.
> 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.
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[ 3.7 ms ] story [ 81.1 ms ] threadhttps://news.ki.se/how-brain-waves-shape-our-sense-of-self
> 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!”
That's a pretty direct causal link between a measurable brain state and something as fundamental as "where does my body end?"
> 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.
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?
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.
You always hear about how something is an extension of the body to the best athletes.
I wonder if the brain can experience if clothing, tools, bikes are part of the body?
That's the limit of "you"? Sounds more like a sampling rate/processing speed of the sense of touch.
https://duckduckgo.com/l/?uddg=https%3A%2F%2Fneurophysics.uc...