Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

We Induced Smells With Ultrasound

writetobrain.com

Post reply on HN
Print view View original

111–120 of 198 posts

Re: We Induced Smells With Ultrasound

#111

Post by isoprophlex »

exr0n wrote: post #104
isoprophlex wrote: post #102

I wonder if this makes you smell "laurax" or "olfactory white" if it glitches and triggers every receptor site simultaneously https://en.wikipedia.org/wiki/Olfactory_white

That's a really interesting concept! The wiki page right now ends in "example of a combination of smells that neutralise each other", which makes me wonder if the "olfactory white" combinations are actually tuned to neutralize? I suspect what we're hitting is a bunch of receptors, and the brain is interpretting it as a common strong and evolutionarily important smell (which I assume has stronger pathways by default).

I was an organic chemist, and as such worked I've worked in various "wet" laboratories. All of them had store rooms and cabinets with hundreds or thousands of bottles filled with horribly smelling goop. Besides the occasional terpenoid (naturally occurring things smelling like menthol, cloves or cinnamon) nearly everything there was liquid death.

These smells have everything: Harsh solvent-like stuff like strong alcohol or glue, rotten fish amines, off-sweet halocarbons, things like burnt plastics, excrement, or stuff that defies description as to their lingeringly terrible sensation of olfactory wrongness (selenium compounds).

There is actually a thing called "cadaverine", that should tell you enough.

Still, every sufficiently large storage space I rememebet had this identical, not unpleasant, thickly sweet, but not easily defined smell.

So to conclude, I think it's a brain glitch when we input everything, all the smells, at the same time.

Re: We Induced Smells With Ultrasound

#112

Post by exr0n »

londons_explore wrote: post #97

How do the power levels here compare with say a baby ultrasound? What are the chances baby ultrasounds are doing this unintentionally?

Woah, that would be wild! It seems like most neonatal ultrasound reaches peak internal pressures of few-hundred kPa to 2 MPa. We ranged from 150-250 kPa. So, a little lower than the lower end of prenatal diagnostic imaging.

So, the pressures are high enough to be stimulating them! But most diagnostic imaging happens at 1-20 MHz, while most neurostimulation seems to occur at few-hundred kHz (we were at 300 kHz, on the mid-high end). So I don't think it's likely that babies are being sent smells?

Re: We Induced Smells With Ultrasound

#113

Post by exr0n »

polishdude20 wrote: post #19
cellular wrote: post #10

Those few smells of extremes (garbage /clean air) make me think they are saturating the sensors.

I'm thinking it could be that we are very attuned to smelling bad smells because it's for safety.

Totally agree with both points! I would love to see what happens with more fine-grained control of the ultrasound.

Re: We Induced Smells With Ultrasound

#114

Post by exr0n »

SV_BubbleTime wrote: post #80
qlm wrote: post #62

Very cool, although I found the link to LLMs toward the end to be a little odd.

Definitely, it’s a “we know the only thing anyone cares about right now is AI, so, look this is kind of like AI, sort of, if you squint”

Haha, luckily not! It's a very speculative link, so we didn't want to talk about "AI" too much in the main post. But we originally got interested in this concept because we are interested in other forms of input to the brain (other than the classic reading, listening, watching, etc). The nose is interesting because it seems to have many independent basis vectors and very sharp discrimination ability, so it might be a sensor into which you can pack many inputs. LLMs are just a proof-by-example that ~1k input dimensions is enough to really encode semantic meaning.

Re: We Induced Smells With Ultrasound

#115

Post by exr0n »

heywoods wrote: post #77

Interesting that the smells they were able to trigger seem to be related to basic survival. Smoke bad. Rotting food bad. Fresh air good.

Totally! We think this is because the brain is hard-wired evolutionarily to interpret smells by danger level first. So maybe there's just more "bad smell" receptors, or maybe the brain treats unknown smells as "uh oh, danger". Lots of cool stuff to test!

Re: We Induced Smells With Ultrasound

#117

Post by exr0n »

a-dub wrote: post #50
DrewADesign wrote: post #33

Earlier quoted context omitted.

If they’re using enough ultrasound energy to create a physical reaction inside the subjects head strong enough to smell like a burning camp fire, I can’t imagine they’d survive long enough to report it. Maybe I’m misunderstanding your implication?

maybe the ionized oxygen sensation, the ozone, the garbage and smoke are like a thin film of garbage and smoke particles in the nasal cavity experiencing mechanical stimulation. the mr guidance seems like a good idea, but the actual mount and targeting sounds crude, what are the odds it's just in the nasal cavity warming up and activating the gross stuff that lives in there? i wonder if some kind of inhalable anesthe…

Great idea for a control! Will have to try it if we set this up again..

Re: We Induced Smells With Ultrasound

#120

Post by exr0n »

virgil_disgr4ce wrote: post #70

OK, I want to meet these guys. This writeup has several breathtaking (if you will) passages. Like: > "We found different scents by steering the beam over ~14 mm (20 degrees at 4 cm radius). The distance between freshness and burning was ~3.5 mm." > "The olfactory system potentially allows writing up to 400, if not 800 due to two nostrils, dimensions into the brain. That is comparable to the dimensionality of latent s…

<3 email me or dm us on twitter! links on the post.
Post reply on HN