Nerve impulses and sound perception

[Acme]

That is still evolving when it comes to understanding how our ears work.

 

Maybe this will interest you guys. Oppenheim and Magnasco end their paper with that tantalizing idea:

That's an unfortunate choice of reference. While the original paper is interesting, your citation is a creationist rag which tries to use the original work as an argument for 'intelligent design'. You can probably hear me gagging from there. At least they reference the original.

 

Full paper: Human Time-Frequency Acuity Beats the Fourier Uncertainty Principle

Review: Human Hearing Is Highly Nonlinear

 

Meanwhile, on reflection of whats said in this thread, my understanding of this thread are as follows:-

 

1) Speed of sound is the speed of transfer movement of molecules to the adjacent molecules .

2) The speed got nothing to do with the oscillation of (air) molecules.

3) The frequency of the oscillation produces sound by creating sound pressure.

4) A slight vibration of 1e-8mm in the ear drum is detectable by us which is close to 0dB.

5) The eardrum membrane area is about 65 mm2.

6) The most the eardrum could travel when vibrating is not likely to exceed 0.5cm. ( I am guessing here because thats the diameters of the eardrum)

7) Hair cells length is much smaller than the eardrums diameter.

8) When hair cells vibrate at 20kHz. The total distance in one second could not be more a few meters considering they are less than 1 mm lenght. ( Something is not right with this statement)

9) Total distance per frequency even at the max of 20kHz is still within the transmission speed of our fastest nerve system (120m/s) and therefore all information could be transferred to brain without loss.

10) However, I believe the neural transmission speed in our ears is about 8m/s only.

 

Am I getting closer? At least now I am clear why the speed of sound is immaterial.

Looks closer, but it's late and I spit up a little on myself after that article so I won't go point by point. Glad you have the speed is immaterial down. I recommend reading those 2 articles that StringJunky posted as they are very informative. Guten nacht.

[StringJunky]

 

 

That is still evolving when it comes to understanding how our ears work.

 

All theories are constantly evolving, that's why scientists don't think of them as absolute truths or laws. Thinking of them like this keeps their mind open to change. This is the fundamental difference between science and religion.

 

 

10) However, I believe the neural transmission speed in our ears is about 8m/s only.

It actually appears to be 20m/s and conduction time over 2.5cm cochlear nerve length is 1.25ms. That equates to a maximum possible firing rate of 800 impulses/second, although I'm sure there will be a short latency for recharging making it a bit less ...likely the 600 I mentioned earlier.

[studiot]

Good morning MayIKnow and congratulations for hanging in there with reasoned discussion about your points. So much better than many who come here to ‘discuss’ an idea.

+1

 

I did put up (post#32) a list of properties designed to find out which ones you have some knowledge of, but there has been so much activity in this thread, perhaps you missed it?

 

Anyway to continue the story, I like your bucket of leaves analogy but you (and everyone else) has so far missed one thing from my list.

 

Filtering.

 

Suppose you had a supersnail that threw away every red leaf or every other leaf or every wet leaf?

That would also reduce the size of the task.

 

We filter out most of our sensory input.

We do not feel or hear out footfall or our clothes moving against our body.

We only notice temperature if it goes up or down dramatically and so on.

 

Now I also mentioned the spatial distribution.

We receive sound from all around us, but we filter out much of this.

Particularly if our other senses tell us that the sound or its source are of no consequence.

Whilst standing safely on the pavement we can hold a conversation, ignoring the roar of the traffic we can see passing by.

But when we step into the roadway we become sensitive to traffic sounds from behind and the side.

 

Transients again. I note the paper quoted by Acme refers to transients.

It also refers to one way how our sensory system can get around physical transmission limits such as Shannon’s theorem and the uncertainty principle is waves.

This will lead to a discussion of buffering and multiplexing, but I will leave tha till next time.

 

There is, of course, a second aspect to spatial distribution.

Our sense of hearing is binaural – we hear in stereo.

Again I will leave the detail till next time.

 

A final observation.

Some of the processing is done in the physical world by physical processes.

Some is done in the mental world by software processes.

Just like a computer.

Edited March 3, 2015 by studiot

[MayIKnow?]

That's an unfortunate choice of reference. While the original paper is interesting, your citation is a creationist rag which tries to use the original work as an argument for 'intelligent design'. You can probably hear me gagging from there. At least they reference the original.

 

Full paper: Human Time-Frequency Acuity Beats the Fourier Uncertainty Principle

Review: Human Hearing Is Highly Nonlinear

 

Looks closer, but it's late and I spit up a little on myself after that article so I won't go point by point. Glad you have the speed is immaterial down. I recommend reading those 2 articles that StringJunky posted as they are very informative. Guten nacht.

 

 

Thanks for the "correct" link.

 

I did read StringJunky's link and was couldnt get passed the first paragraph with asking the same question again. What we hear as a pure tone may not sound like a pure tone as it was determined by period of nueron firing patterns. My nueron firing pattern maybe different from my dog.

 

 

 

The temporal theory of hearing states that our perception of sound depends on the temporal patterns with which neurons respond to sound in the cochlea. Therefore, the pitch of a pure tone would be determined by period of neuron firing patterns, either of single neurons or groups as described by the volley theory.

[StringJunky]

 

 

Thanks for the "correct" link.

 

I did read StringJunky's link and was couldnt get passed the first paragraph with asking the same question again. What we hear as a pure tone may not sound like a pure tone as it was determined by period of nueron firing patterns. My nueron firing pattern maybe different from my dog.

 

I'll bet the firing rate is different. so what? It'll sound 'pure' to both. There's only a single frequency to detect and they both hear it ...the only difference might be amplitude.

Edited March 4, 2015 by StringJunky

[MayIKnow?]

Good morning MayIKnow and congratulations for hanging in there with reasoned discussion about your points. So much better than many who come here to ‘discuss’ an idea.

+1

 

I did put up (post#32) a list of properties designed to find out which ones you have some knowledge of, but there has been so much activity in this thread, perhaps you missed it?

 

Anyway to continue the story, I like your bucket of leaves analogy but you (and everyone else) has so far missed one thing from my list.

 

Filtering.

 

Suppose you had a supersnail that threw away every red leaf or every other leaf or every wet leaf?

That would also reduce the size of the task.

 

We filter out most of our sensory input.

We do not feel or hear out footfall or our clothes moving against our body.

We only notice temperature if it goes up or down dramatically and so on.

 

Now I also mentioned the spatial distribution.

We receive sound from all around us, but we filter out much of this.

Particularly if our other senses tell us that the sound or its source are of no consequence.

Whilst standing safely on the pavement we can hold a conversation, ignoring the roar of the traffic we can see passing by.

But when we step into the roadway we become sensitive to traffic sounds from behind and the side.

 

Transients again. I note the paper quoted by Acme refers to transients.

It also refers to one way how our sensory system can get around physical transmission limits such as Shannon’s theorem and the uncertainty principle is waves.

This will lead to a discussion of buffering and multiplexing, but I will leave tha till next time.

 

There is, of course, a second aspect to spatial distribution.

Our sense of hearing is binaural – we hear in stereo.

Again I will leave the detail till next time.

 

A final observation.

Some of the processing is done in the physical world by physical processes.

Some is done in the mental world by software processes.

Just like a computer.

 

 

Good morning Studiot. I owe it to you guys for the patience. It is usually annoying and frustrating to put across a point to someone who has no fundamental knowledge of the subject he is talking about. I was worried that mod might lock me out for being a troll with those silly questions..

 

 

Anyway...I did notice your post #32 and I need time to understand them thoroughly which may take a few days. Meanwhile, my untrained mind do not see the relevance of filtering for the purpose of the original question.

 

I am aware that we filter out most of the sound. My understanding is the process takes place in the brain not in the ear except for frequencies outside our hearing range. Going back to your red leaves analogy and supersnail; it would not explain if I am listening to a beautiful solo piano rendition in darkness. And let's say the noisefloor of the room is about 40dB due to the air conditioning system, you may hear them in the beginning but eventually your brain would ignore(filter out) those disturbing noise.

 

In the example above, the supersnail would still pick all the leaves and put it in the basket and the brain would decide whether to pay attention to the red leaves or not. Am I correct?

 

There are many occasions where what sounded as noise and under normal circumstance the brain would dismissive them as noise may somehow beginning to sound meaningful like here.

 

We do not feel or hear out footfall or our clothes moving against our body.

We only notice temperature if it goes up or down dramatically and so on.

 

 

Can we take another example here? Let's say a gradual increase of 1kHz at 0.1dB per second. Normally, we couldnt detect a 0.1db change. So let's say we start playing 1 khz signal at 80dB and increase the volume gradually 0.1dB every second. So after 60 seconds the SPL would be at 110dB. 110dB is still below the pain threshold. Could we detect the change or not?

Edited March 4, 2015 by MayIKnow?

[Acme]

Thanks for the "correct" link [Acme].

You're welcome.

 

I did read StringJunky's link and was couldnt get passed the first paragraph with asking the same question again. What we hear as a pure tone may not sound like a pure tone as it was determined by period of nueron firing patterns. My nueron firing pattern maybe different from my dog.

Well, keep reading.

Temporal theory

...

High frequencies

 

Neurons have a maximum firing frequency which falls within the range of frequencies we can hear. In order to be complete, rate theory must somehow explain how we distinguish pitches above this maximum firing rate. The volley theory, in which groups of neurons cooperate to code the temporal pattern, is an attempt to make the temporal theory more complete, but there are still frequencies too high to see any synchrony in the auditory nerve firings.

...

Another solution

 

Modern research suggests that the perception of pitch depends on both the places and patterns of neuron firings. Place theory may be dominant for higher frequencies.[4] However, it is also suggested that place theory may be dominant for low, resolved frequency harmonics, and that temporal theory may be dominant for high, unresolved frequency harmonics.[5] ...

And from the Volley theory link:

...

Present thoughts

 

Ultimately, as new methods of studying the inner ear came about, a combination of place theory and frequency theory was adopted. Today, it is widely believed that hearing follows the rules of the frequency theory, including volley theory, at frequencies below 1000 Hz and place theory at frequencies above 5000 Hz. For sounds with frequencies between 1000 and 5000 Hz, both theories come into play so the brain can utilize the basilar membrane location and the rate of the impulse.[10]

...

While all questions on how we hear are not answered, nowhere in any of this reading have I read that we have a loss of information as your initial question suggests. Common sense tells me that were it true we were missing out on something -other than frequencies outside our normal range- the experts would be all over the issue.

Edited March 4, 2015 by Acme

[MayIKnow?]

While all questions on how we hear are not answered, nowhere in any of this reading have I read that we have a loss of information as your initial question suggests. Common sense tells me that were it true we were missing out on something -other than frequencies outside our normal range- the experts would be all over the issue.

 

I thought we must be losing information due to the slow transmission velocity of nerve system as compared to the speed of sound. However, now it has been clearly explained that velocity of sound got nothing to do with what's we are hearing.