Sound transmission to the brain

[Snoopy1234]

Water antenna
Humantenna

 

[hutchphd]

It would be helpful if you asked a question. Putting ? at the end does not create a question.

 

[berkeman]

Summary:: hi guys I'm new to the forum and i hope i haven't got the wrong section. So since electrolytes are conductors and our human body is an electrolyte conductor? because we cannot listen to the radio waves of radio stations eg. music? Do not answer me by making fun of me, because it is not the first time that I have asked this question but I have not yet had satisfactory answers

Water antenna
Humantenna

Welcome to PhysicsForums, Snoopy.

It takes more than a conductor to make a radio receiver. The simplest receiver is a rectifying diode "envelope detector" for AM radio signals. That's how the simplest radios were initially built (Crystal Radios). I've heard some "urban legends" of dental work forming such a rectifying envelope detector so that some people could hear nearby AM radio stations, but I will have to look around a bit to see if I can find a valid reference.

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

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

 

[Snoopy1234]

Welcome to PhysicsForums, Snoopy.

It takes more than a conductor to make a radio receiver. The simplest receiver is a rectifying diode "envelope detector" for AM radio signals. That's how the simplest radios were initially built (Crystal Radios). I've heard some "urban legends" of dental work forming such a rectifying envelope detector so that some people could hear nearby AM radio stations, but I will have to look around a bit to see if I can find a valid reference.

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

View attachment 273111

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

yes mr berkeman , I already knew this, even being close to a conductor the signal is demodulated and therefore heard, I want to know if in the absence of metal inside or outside the body, radio stations can be heard. so the problem lies in the fact that the signal can be demodulated by ions in the body but how can it be transduced into vibration for bone conduction?

 

[anorlunda]

the fact that the signal can be demodulated by ions in the body

Huh? Where did you read that?

 

[hutchphd]

It is possible to hear strong AM signals in the silver amalgam fillings of your teeth. The oxide layer on a bad filling makes a point-contact diode and bone conduction does the rest.
I remember as a kid making "cat's-whisker" detectors using an oxidized 5 cent coin (they were silver back then) and a pencil point but an earphone was required.
I don't know, but teeth must somehow be piezo electric? But metal oxide was required...not just an electrolyte

 

[Dale]

So since electrolytes are conductors and our human body is an electrolyte conductor? because we cannot listen to the radio waves of radio stations eg. music?

Yes, the human body is an electrolytic conductor.

I don’t understand the second question. It seems like an answer to a different question. Are you perhaps Spanish speaking where the word “porque” is translated as “why” in a question and as “because” in an answer?

 

[berkeman]

the signal can be demodulated by ions in the body

To demodulate a signal, it takes a non-linear device like a diode or transistor. I don't think there are such structures in the human body (other than the dental fillings already mentioned), but if you have a reference I'd be interested in reading it. Did you read the Modulation Wikipedia article that I linked? Can you see why you need a non-linear process or device to perform demodulation of modulated signals?

 

[hutchphd]

But what actually produces the sound vibration? Check this out, it discusses certain ceramic caps that sing with voltage...maybe teeth do?? But you need the oxide boundary to rectify the signal: it is why electrolytic caps need a particular voltage bias.
Surely some Master's thesis has looked into this exact question...

 

[Snoopy1234]

To demodulate a signal, it takes a non-linear device like a diode or transistor. I don't think there are such structures in the human body (other than the dental fillings already mentioned), but if you have a reference I'd be interested in reading it. Did you read the Modulation Wikipedia article that I linked? Can you see why you need a non-linear process or device to perform demodulation of modulated signals?

thanks guys for your interest, I'm Italian so I'm sorry for my English, and because I don't understand yours. however apart from this, I posted the domabda precisely because I do not know if there is something that can demodulate the signal in our body, I already knew about the fact of the fillings but in the absence of any form of metal inside or outside the body, you can demodulate? through the "humantenna" projects I have discovered that there must be a good grounding as actually mentioned in the first photo, but how can I do this if people have shoes?

 

[Snoopy1234]

To demodulate a signal, it takes a non-linear device like a diode or transistor. I don't think there are such structures in the human body (other than the dental fillings already mentioned), but if you have a reference I'd be interested in reading it. Did you read the Modulation Wikipedia article that I linked? Can you see why you need a non-linear process or device to perform demodulation of modulated signals?

.

But what actually produces the sound vibration? Check this out, it discusses certain ceramic caps that sing with voltage...maybe teeth do?? But you need the oxide boundary to rectify the signal: it is why electrolytic caps need a particular voltage bias.
Surely some Master's thesis has looked into this exact question...

yes mr hutchphd what I need to understand is how I can transform the electrical signal into vibration, i.e. the reverse work of the human eardrum or if the electrical signal can be heard directly by the earliest auditory receptors

 

[Snoopy1234]

Yes, the human body is an electrolytic conductor.

I don’t understand the second question. It seems like an answer to a different question. Are you perhaps Spanish speaking where the word “porque” is translated as “why” in a question and as “because” in an answer?

hello Mr. Dale I apologize for my English, but I am Italian. the second question refers to the probable ability to listen to radio stations without any external or internal metal support

 

[Dale]

hello Mr. Dale I apologize for my English, but I am Italian.

Welcome! Do you know if the same Italian word is translated as “why” and “because” in English? I know that is the case for Spanish, and there is a lot of similarity between Spanish and Italian.

second question refers to the probable ability to listen to radio stations without any external or internal metal support

I do not think that is possible. At least, I have never heard of that happening, and I don’t see a plausible way that would happen naturally.

 

[Snoopy1234]

Welcome! Do you know if the same Italian word is translated as “why” and “because” in English? I know that is the case for Spanish, and there is a lot of similarity between Spanish and Italian.

in Italian there is only one word to translate the two terms and that is "perche'" , the meaning lies in the fact that in Italian we tend to take into account the intonation of a word

 

[Snoopy1234]

I do not think that is possible. At least, I have never heard of that happening, and I don’t see a plausible way that would happen naturally.

and then for what reason can a metal obturation demodulate a signal and instead the human body, which is also a conductor, cannot? depends on signal strength or wave shape ??

 

[Dale]

and then for what reason can a metal obturation demodulate a signal and instead the human body, which is also a conductor, cannot? depends on signal strength or wave shape ??

It requires more than just a conductor. It requires at least a diode, as @hutchphd described earlier

 

[berkeman]

and then for what reason can a metal obturation demodulate a signal and instead the human body, which is also a conductor, cannot? depends on signal strength or wave shape ??

By "obturation" I think you are referring to the metal dental fillings that were referenced earlier?

As was mentioned, it's not just the metal, it's the presence of an oxide layer on the surface which helps to form an an electrical diode structure. That is the non-linear circuit element used in the envelope detection circuit for AM radio signal demodulation. In a crystal radio, it is the interface between the thin metal "whisker" wire contacting the crystal surface. Without a diode or a transistor, you will not get demodulation to get the original information signal back from the EM.

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

 

[Snoopy1234]

By "obturation" I think you are referring to the metal dental fillings that were referenced earlier?

As was mentioned, it's not just the metal, it's the presence of an oxide layer on the surface which helps to form an an electrical diode structure. That is the non-linear circuit element used in the envelope detection circuit for AM radio signal demodulation. In a crystal radio, it is the interface between the thin metal "whisker" wire contacting the crystal surface. Without a diode or a transistor, you will not get demodulation to get the original information signal back from the EM.

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

hello mr berkemann, I have carefully read your answer and in conclusion it is the presence of a diode or rectifier the last part of the journey. For this we need an oxide and I found it and it is the nitric oxide present in our body precisely to allow the passage of current between neurons. I hope this will be enough to conclude my work precisely because I really care about this project and I am consulting with various professors of my university, and in this case one of my project mates suggested me to use another type of modulation like the impulse one, that is the PWM, can they be used ??

 

[Dale]

it is the presence of a diode or rectifier the last part of the journey. For this we need an oxide and I found it and it is the nitric oxide present in our body precisely to allow the passage of current between neurons

I haven’t seen any indication that normal physiological nitric oxide would act as a diode. Isn’t it normally in solution?

 

[Snoopy1234]

I haven’t seen any indication that normal physiological nitric oxide would act as a diode. Isn’t it normally in solution?

already in fact Mr. Dale it was a mistake, suggested by my helpers, however as I will already tell berkeman, they told me to use more than one em wave, the second with different frequency to dampen the carrier and take only the informative signal through the principle of the mixer. can that be a good idea?

 

[berkeman]

already in fact Mr. Dale it was a mistake, suggested by my helpers, however as I will already tell berkeman, they told me to use more than one em wave, the second with different frequency to dampen the carrier and take only the informative signal through the principle of the mixer. can that be a good idea?

What mixer? It sounds like your helpers may need to brush up on their mixer/modulation/demodulation theory...

 

[Snoopy1234]

What mixer? It sounds like your helpers may need to brush up on their mixer/modulation/demodulation theory...

the concept is precisely that of the signal mixer in which the external radio signal is made to interfere with an internal wave, I cannot explain it well I am sending you some references

 

[berkeman]

the concept is precisely that of the signal mixer in which the external radio signal is made to interfere with an internal wave, I cannot explain it well I am sending you some references

I replied to your PM. You cannot demodulate the information signal from the carrier signal without using transistors and/or diodes. You need the non-linear circuit elements in order to perform the "mixer" and "demodulator" functions in a receiver.

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

 

[Snoopy1234]

What mixer? It sounds like your helpers may need to brush up on their mixer/modulation/demodulation theory...

https://it.m.wikipedia.org/wiki/Supereterodina
This is the link in italian,
i can't find the english counterpart

 

[berkeman]

I already linked to the English Wikipedia page about demodulation and mixers.

Anyway, if your professors at university are letting you spend time on exploring how a linear system (the human body without any circuitry aids) can demodulate any form of modulation (ASK, AM, FM, OOFDM, etc.), perhaps they want you to realize that it is impossible, and explain why it is impossible in your paper.

What year of university is this project for? What is your background so far in math, physics, and EE?

 

[Snoopy1234]

I already linked to the English Wikipedia page about demodulation and mixers.

Anyway, if your professors at university are letting you spend time on exploring how a linear system (the human body without any circuitry aids) can demodulate any form of modulation (ASK, AM, FM, OOFDM, etc.), perhaps they want you to realize that it is impossible, and explain why it is impossible in your paper.

What year of university is this project for? What is your background so far in math, physics, and EE?

It's useless to use math if we haven't gotten very far, so in the end you tell me that it's not possible to do this with em waves in any way, and so what can be another way to make the brain hear little sounds? the only way that comes to mind is the capacitative coupling but I don't know more, what do you tell me, also because in this case we eliminate the problem of alternating current and we act continuously, but then later how can we make the sounds heard to the brain? please give me satisfactory answers because i am destroyed by the previous answers

 

[Snoopy1234]

hi guys, sorry if I still bother you with my questions. This question is a second part, the theme is always the same, that is to transmit sounds to the brain at a distance and without the use of equipment to the recipient. I abandoned the idea of transmission with em waves, due to the impossibility of straightening the alternating current (thanks to the help and cooperation of Berkemann), in this case I deepened the neurological part of the project, and I noticed that the brain receives stimuli , which are translated from a sound vibration to an electrical impulse, through 3 variables (duration, intensity, frequency), to the neurons. So in this case the intensity is comparable to the signal amplitude. In conclusion, what can be the best way to transmit impulses? With electromagnetic or electrostatic induction?
Ps: Guys I hope you can help me complete this project, I'm going crazy and can't find a light at the end of the tunnel

[Two threads on the same topic have been merged by the Mentors]

 

[Drakkith]

It cannot be done at this time, and probably not for a very long time, if ever. The inner ear takes a vibrational motion of small hairs and turns that into signals that are sent to the brain through a long chain of neurons that both transmit and process these signals. Your goal would be to excite some part of this chain in exactly the right way as to mimic the signal from a real sound wave that has been detected and possibly been partially processed. And since we don't fully understand the processing steps that take place, you're already running into a large dead end even before we talk about HOW you would induce a signal in these neurons.

Targeting the first cells in the chain, the ones that convert the vibrational motion into electrical impulses is almost as problematic. The problem is that you have to somehow target the exact right cells and then somehow activate them without direct contact via an electrode. I know of no way to do either of these.

The first problem is already basically insurmountable, as you would have know exactly where the right cells are in the recipient's body to within a very, very small tolerance (on the order of micrometers), and you would also need to immobilize the intended recipient to keep them from moving and spoiling your 'aim'. Just mapping out the exact cells to target is probably not possible without seriously expensive equipment and procedures. And you would need to do this for every recipient, as every person is built slightly different.

Then you run into the problem of how to activate these cells from a distance. The only conceivable way to do so would be through electromagnetic radiation or induction, but I know of no way to use either of these to activate neurons at the required resolution. Even modern electromagnetic induction stimulation typically stimulates sections of the brain much, much larger than single neuron. Also note that the frequency of EM waves required to get single-cell resolution is about 3 THz, which is strongly absorbed by the human body and won't get through enough tissue to reach the inner ear or brain.

The equipment needed is also not practical. Quote from this source:

TMS requires large power sources (≤20,000 A)30 to drive the magnetic fields, as the coils are large and far from the brain tissue. Together, these limitations reduce their feasibility as chronic neurotherapeutic applications.

Also, regarding 'resolution' as I mentioned above (bolding mine):

In TMS, the neuronal activation is generated via electromagnetic induction, whereas in tDCS, it is generated by electric current injection through the scalp and calvarium. In both of these methods, the brain is activated without a direct interface between neural tissue in the brain and the stimulus source. However, the application of these techniques is affected by poor reproducibility resulting from variability of induced electric field due to heterogeneous brain tissue as well as anthropomorphic factors such as shape of skull and scalp-to-cortex distance. The lack of spatial selectivity is critical because in many current and emerging applications, the target area for producing the intended effects is in the immediate vicinity of areas that, if stimulated, produce side effects11, 29.

Unfortunately, without some sort of receiving equipment implanted into the brain or ear your idea simply isn't possible at this time.

 

[Drakkith]

It's useless to use math if we haven't gotten very far, so in the end you tell me that it's not possible to do this with em waves in any way, and so what can be another way to make the brain hear little sounds?

As I said in your new thread on this topic, without implanting some sort of receiving equipment, this just isn't possible at this time. Anyone interested can see my post here.

 

[Dale]

Why can’t you just use speakers?