Thank you for this video and the high-quality free course in general! I noticed, however, at the end of the video a slight mistake in the example of 500 and 505 Hertz frequency- the higher that is 505Hz should be closer to the base and the lower that is 500Hz should be closer to the top. Best regards!
I have a congenitally deaf son with a cochlear implant, now almost thirty years old. I wonder if prestin activity can be determined via some sort of genetic testing. Does anyone here know?
Your knowledge is impressive, but I would like to challenge a few things. You say that people without prestin are deaf, but this surely cannot be right. In order to move, the outer hair cells need a signal, and we assume surely that this signal, for what is a positive feedback process, is comes from the inner hair cells, do we not not? If they produce so little signal without help, how can this work? In any case, our hearing covers such a vast range of amplitudes, a ratio of even 60dB is 1000 times in amplitude terms, that to go from hearing to deaf without outer hair cell function is just ridiculous. Assuming you are right about the prestin experiment, there has to be another answer. Maybe in knocking out prestin something else was knocked out? Or maybe the ear doesn't work as we think at all, and something else is going on? I would also ask how convinced you are that hair cells are as finely discriminating of frequency as you say (1000 and 1005 Hz example you give). My understanding is that fine frequency discrimination takes place in the brain, hence the need for fast triggering of hair cells, and even then we assume that they do not fire on every cycle (although you talk of fast depolarisation needed in relation to 20kHz this is not right - neurons fire in millisecond terms, too slow for 20kHz, which is probably why we do not have good frequency discrimination above a few kHz. ) The nerve output from the cochlea is said to not discriminate finely, hence frequency masking, as taken advantage of in modern audio compression. Finally, I think, like many others, you talk of the cochlea membrane being 'fine tuned'. I don't believe anything like resonance is possible in a fluid containing structure (I think something else is going on, but nothing to do with resonance or conventional filtering). Maybe, with positive feedback from outer hair cells, but this has to be a very delicate balancing act to avoid oscillation. How could such a balancing act evolve if there was no hearing without outer hair cells? Do all animals have outer hair cells - I seem to remember not.
Thank you for this video and the high-quality free course in general! I noticed, however, at the end of the video a slight mistake in the example of 500 and 505 Hertz frequency- the higher that is 505Hz should be closer to the base and the lower that is 500Hz should be closer to the top. Best regards!
Thanks for the fantastic lecture 👍 It was great listening to you !
So cool! Thanks for this comprehensive video; I like your passion for this material too :)
Thank you so much. It was very helpful.
You're amazing, thank you so much :)
Great video.
This is the best video ever.
Tank you
amazing explanation. thank you very much, used this for teaching students too.
Best explication ever
I have a congenitally deaf son with a cochlear implant, now almost thirty years old. I wonder if prestin activity can be determined via some sort of genetic testing. Does anyone here know?
4:20 & 6:14
Your knowledge is impressive, but I would like to challenge a few things. You say that people without prestin are deaf, but this surely cannot be right. In order to move, the outer hair cells need a signal, and we assume surely that this signal, for what is a positive feedback process, is comes from the inner hair cells, do we not not? If they produce so little signal without help, how can this work? In any case, our hearing covers such a vast range of amplitudes, a ratio of even 60dB is 1000 times in amplitude terms, that to go from hearing to deaf without outer hair cell function is just ridiculous. Assuming you are right about the prestin experiment, there has to be another answer. Maybe in knocking out prestin something else was knocked out? Or maybe the ear doesn't work as we think at all, and something else is going on?
I would also ask how convinced you are that hair cells are as finely discriminating of frequency as you say (1000 and 1005 Hz example you give). My understanding is that fine frequency discrimination takes place in the brain, hence the need for fast triggering of hair cells, and even then we assume that they do not fire on every cycle (although you talk of fast depolarisation needed in relation to 20kHz this is not right - neurons fire in millisecond terms, too slow for 20kHz, which is probably why we do not have good frequency discrimination above a few kHz. ) The nerve output from the cochlea is said to not discriminate finely, hence frequency masking, as taken advantage of in modern audio compression.
Finally, I think, like many others, you talk of the cochlea membrane being 'fine tuned'. I don't believe anything like resonance is possible in a fluid containing structure (I think something else is going on, but nothing to do with resonance or conventional filtering). Maybe, with positive feedback from outer hair cells, but this has to be a very delicate balancing act to avoid oscillation. How could such a balancing act evolve if there was no hearing without outer hair cells? Do all animals have outer hair cells - I seem to remember not.
My hearing loss 😢 plice
Help me help 😭 me
Help me plice help me help 😭 me
So many earrings, they must act as an amplifier too. I am wondering why Békésy has overseen this.