Sound and the Brain

[Zolar V]

My question stems from a previous question that i had about how the light signal is interpreted by the brain through the optic nerve.

 

How does the Brain process sound? is it in a similar fashion that the optic nerve is? that is does a nerve bundle or thread correspond to a frequency/color?

[insane_alien]

well the sounds vibrations are picked up by hairs in your chochlea(sp? big spiral thing in your ear that looks a bit like a snail shell). each of these hairs is connected to a nerve. The hairs are of different lengths and position within the chochlea and thus resonate at different frequencies. when they resonate a signal is sent down the nerve to the auditory processing centers of the brain.

[Zolar V]

so it would appear that each frequency that we can here is hardwired to the brain via a specialized nerve?

[StringJunky]

It's not that each nerve is specialized but because each hair is of a different length, so it resonates sympathetically to a particular frequency which correlates to its length.

[Zolar V]

The nerve is specialized because it is only passing 1 signal, that is the signal being generated by the hair, to be passed to the brain.

[iNow]

The firing pattern is what matters. No sensation comes from one cell alone, nor from any specialized nerves. Different cilia (small hairs) are suspended in inner ear fluid. Those cilia are different lengths and different tensile capacities, and bend at different frequencies and magnitudes of sound. When those cilia bend, they cause the nerve cells to which they are attached to fire. The location of the cells which fire, as well as the number of cells firing, determines the interpretation of the sound.

 

http://www.dls.ym.edu.tw/chudler/hearing.html

[Zolar V]

would it then be possible to inject certian sounds by following the firing patterns?

aka, if you were to recieve like comms from something for a forward deployed unit, could some sort of device properly translate the comms into the firing patterns and inject/stimulate that area of the nerves via implant?

[iNow]

Yes, that's definitely possible in theory. However, you need to recognize the technological challenges involved in doing it well. If you're new to this arena, you may look up some of the work which has been done with transcranial magnetic stimulation, or with Braingate.

[Mr Skeptic]

would it then be possible to inject certian sounds by following the firing patterns?

 

It's called a cochlear implant

[Zolar V]

Yes, that's definitely possible in theory. However, you need to recognize the technological challenges involved in doing it well. If you're new to this arena, you may look up some of the work which has been done with transcranial magnetic stimulation, or with Braingate.

 

Transcranial_magnetic_stimulation, is pretty interesting.

According to the wiki article they are currently using it in to stimulate or otherwise affect the brain and see its response. ie passing the stimulation over the motor areas of the brain and seeing how the muscles react.

 

IMO they should stop studying the brain with it, because it is basically useless too, and try its affects on the nerves below a point where one is paralyzed.

if it were to stimulate the nerves with the correct signal, would the muscles react accordingly. yes they should because all nerves really are are conduits (akin to wires) for signal to pass. Transcranial Magnetic Stimulation is at best a diagnostic tool.

 

However it does show the potential to stimulate nerves via an external medium to have a proposed/known effect.

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It's called a cochlear implant

 

That is quite the interesting device, I have looked at it once before.

It appears that the device works by transmitting sound frequencies through electrodes to the inner ear area, not directly to the nerves themselves.

 

with out current technology that is probably the better way to do it. manly i say this because if were were to match 1 electrode to 1 hair/nerve pair we would defiantly fill up our ear with electrodes.

 

What i am talking about is stimulating the nerves directly, so there is no hearing loss, and all sound is "crystal" clear. The main reason why i even thought of this is because while i do my job on a plane, it is very hard to hear other people talking on the various headsets we use. if we were to just use an implant such as this, but connected directly to the nerves we would not have any sort of hearing issues or volume issues that we see aboard aircraft.

 

Again, personally i would like to use this and my eye implant . it just seems like such a good idea. and it appears that it is because it is already being used/researched.

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i really wish i was in college, so i could research this stuff in a lab myself.

/sigh