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

Scientists discover mechanism of hearing

news.ohsu.edu

Post reply on HN
Print view View original

31–40 of 50 posts

Re: Scientists discover mechanism of hearing

#31

Post by mitthrowaway2 »

lr4444lr wrote: post #22
formerly_proven wrote: post #13

Hearing is kind of fascinating if you calculate the power supplied to the eardrum in the ~0 dB range, we're talking about attowatts of sound power generating movements in the single-digit nanometer range, which is still picked up and converted to a neuronal response. Meanwhile the whole thing suppresses the far greater pressure fluctuations due to your heartbeat and other movements quite well, and can reasonably cope…

How do you know those noises are suppressed and not just neurologically "filtered out" by the auditory cortex?

If so, then it's even more stunning that the communication channel to the auditory cortex is quiet enough to carry a massive disturbance + a tiny signal, and still preserve that signal after subtracting out the disturbance.

That would be very difficult to accomplish electronically.

Re: Scientists discover mechanism of hearing

#32

Post by alexpotato »

1letterunixname wrote: post #24

WHAT?! :> I'm at ACL and can't hear a fucking thing. ;) I wonder about the limits of the muscles of the eardrum (TT and stapedius) to prevent hearing damage. For example, I recall awaking one morning being unable to hear because those muscles were isometrically flexing to a degree that prevented the eardrum from move normally. I thought I lost my hearing but then they started to relax over a few minutes. I don't know…

> For example, I recall awaking one morning being unable to hear because those muscles were isometrically flexing to a degree that prevented the eardrum from move normally. I thought I lost my hearing but then they started to relax over a few minutes.

I remember listening to a podcast where one of the guests experienced a highly stressful event. They mentioned that they felt like they couldn't hear anything for a few weeks but the problem eventually went away.

When I heard this, I assumed it was some kind of psychosomatic effect but reading this made me realize that it could also be related to actual physiological responses to stress. (You could argue that psychosomatic responses are also physiological so I'm drawing a distinction between "your brain stopped you from hearing" vs "your body was so stressed out, your ears stopped you from hearing".)

The human body is amazing.

Re: Scientists discover mechanism of hearing

#33

Post by mym1990 »

9wzYQbTYsAIc wrote: post #26
1letterunixname wrote: post #24

WHAT?! :> I'm at ACL and can't hear a fucking thing. ;) I wonder about the limits of the muscles of the eardrum (TT and stapedius) to prevent hearing damage. For example, I recall awaking one morning being unable to hear because those muscles were isometrically flexing to a degree that prevented the eardrum from move normally. I thought I lost my hearing but then they started to relax over a few minutes. I don't know…

> I can consciously make both eardrums vibrate creating a sound like a rumble I can as well when I consciously try to pop my ear drums.

I can as well, it feels like flexing a muscle!

“ Inside the ear is a small muscle called the tensor tympani. When this muscle is tensed, it causes a roaring or whooshing sound in the ear.”

Although a rumble seems a better way to describe the sound.

Re: Scientists discover mechanism of hearing

#34

Post by soulofmischief »

1letterunixname wrote: post #24

WHAT?! :> I'm at ACL and can't hear a fucking thing. ;) I wonder about the limits of the muscles of the eardrum (TT and stapedius) to prevent hearing damage. For example, I recall awaking one morning being unable to hear because those muscles were isometrically flexing to a degree that prevented the eardrum from move normally. I thought I lost my hearing but then they started to relax over a few minutes. I don't know…

What you hear vibrating is not your ear drums themselves, but is a muscle called the tensor tympani. It aids in dampening loud sounds like chewing or screaming. I can also do this.

Re: Scientists discover mechanism of hearing

#35

Post by monkeycantype »

tasty_freeze wrote: post #29
accountofme wrote: post #23

Earlier quoted context omitted.

The brain doesn't compute it, the cochlear is an fft! It is a cone shaped structure (that is curled up) that is covered in hairs and neurons. The fatter end is used for low freq and the thinner end is used for hi freq. So the brain takes audio in the frequency domain, not as continuous samples! (I did an Anatomy degree almost 20years ago now, all from memory)

The person you are responding to is right and your assertion is incorrect. The person you replied to knows the ear delivers a frequency domain representation. They were disagreeing with the FFT part. The FFT is a specific mathematical construction that carries out a Fourier Transform efficiently through a hierarchy of "butterfly" steps. The ear has no such thing. It is just ~20,000 hair cells, each resonant to a spec…

I'm wading into an area I'm not expert, not to assert but to ask, I remember having an electro-mechanical object explained to me, I think it was a variant of this: https://www.retrothing.com/2008/05/the-harmonium-a.html

I can roughly recall the mechanism by which it worked, and was told that this was an analog for how the Fourier transformation worked, and I vaguely remember going through one on paper. The spiral of the cochlear seems an analog of how the harmonium works. Does the earlier poster have a point with regard to the cochlear as a physical object performing a Fourier transform (though perhaps not a fast one)?

Re: Scientists discover mechanism of hearing

#36

Post by 9wzYQbTYsAIc »

mym1990 wrote: post #33
9wzYQbTYsAIc wrote: post #26

Earlier quoted context omitted.

> I can consciously make both eardrums vibrate creating a sound like a rumble I can as well when I consciously try to pop my ear drums.

I can as well, it feels like flexing a muscle! “ Inside the ear is a small muscle called the tensor tympani. When this muscle is tensed, it causes a roaring or whooshing sound in the ear.” Although a rumble seems a better way to describe the sound.

I concur - rumble is a more apt description for me too, but there’s a little whooshing.

This reminds me of an article that I once read (couldn’t find it, but I believe it was about [1] - Quest for Zero-Decibels).

In absolute silence, all sorts of bodily noises crop up - your heartbeat, creaking bones and muscles, popping noises, etc.

[1] https://www.goodreads.com/book/show/7932161-zero-decibels#

Re: Scientists discover mechanism of hearing

#37

Post by samatman »

accountofme wrote: post #23
TaupeRanger wrote: post #20

Earlier quoted context omitted.

It does extract frequency information but not via FFT. Just like the brain computes but not via Turing Machine.

The brain doesn't compute it, the cochlear is an fft! It is a cone shaped structure (that is curled up) that is covered in hairs and neurons. The fatter end is used for low freq and the thinner end is used for hi freq. So the brain takes audio in the frequency domain, not as continuous samples! (I did an Anatomy degree almost 20years ago now, all from memory)

The accurate way of saying this is that the cochlear does Fourier analysis.

Folks around here don't handle ambiguity well, and are treating your comment like it's wrong, rather than basically correct except for a harmless conflation of an algorithm for something with the thing itself.

Ah well.

Re: Scientists discover mechanism of hearing

#39

Post by bigbluedots »

alexpotato wrote: post #32
1letterunixname wrote: post #24

WHAT?! :> I'm at ACL and can't hear a fucking thing. ;) I wonder about the limits of the muscles of the eardrum (TT and stapedius) to prevent hearing damage. For example, I recall awaking one morning being unable to hear because those muscles were isometrically flexing to a degree that prevented the eardrum from move normally. I thought I lost my hearing but then they started to relax over a few minutes. I don't know…

> For example, I recall awaking one morning being unable to hear because those muscles were isometrically flexing to a degree that prevented the eardrum from move normally. I thought I lost my hearing but then they started to relax over a few minutes. I remember listening to a podcast where one of the guests experienced a highly stressful event. They mentioned that they felt like they couldn't hear anything for a few…

That reminds me of the Peril-Sensitive sunglasses from Hitchhiker's Guide to the Galaxy, that go completely dark when the wearer's in danger.
Post reply on HN