🚀 go-pugleaf

On Thu, 28 Sep 2006 21:53:06 -0500, "Mike Rieves" <mriev@hotspam.com>
wrote:

>
>"Bob Masta" <NoSpam@daqarta.com> wrote in message 
>news:451bc030.1306174@news.sysmatrix.net...
>> On Wed, 27 Sep 2006 13:10:28 -0500, "Mike Rieves" <mriev@hotspam.com>
>> wrote:
>>
>> <snip>
>>>
>>>The Neurophone however, is a totally different animal.
>>>I notice that at www.neurophone.com they are talking about ultrasonic
>>>transmission, rather than RF transmission, which I think may be plausible,
>>>though I'm far from an expert on the subject.
>>>
>>
>> It doesn't matter whether it's ultrasound, RF, microwave, magnetic, or
>> electric fields.  The problem is not getting a signal into the head,
>> its getting *many* signals into the head in just the right places to
>> represent the frequency content of each auditory channel.  Even
>> if you drilled a hole and placed an electrode at any site you chose,
>> and pumped the audio signal in directly, you would just get a series
>> of buzzes in time with the signal peaks.
>>
>> Once again, the auditory system is not even remotely like radio
>> or telephones.  The cochlea breaks down the signal into separate
>> frequency components, and each goes to the brain on its own
>> nerve.  If you look at the signal on any one of those nerves, it is
>> a spike train where the spikes per second is proportional to the
>> signal *strength*... not frequency.  The spike rates are in the
>> low 100s of spikes per second... definitely not adequate to
>> encode anything like audio.  If you stuck your electrode or
>> neurophone signal directly into the neuron and applied audio,
>> only the peaks that were large enough to exceed the neuron's
>> threshold would produce spikes.  After the neuron fires its
>> spike, it goes into a "refractory period" where it has to recover
>> before it can fire another spike.  So, no possible way to send
>> audio over a nerve.  All the nerve carries is information about
>> the envelope of its single frequency component, sort of like
>> one column of LEDs on one of those home stereo spectrum
>> displays, where there are different columns of LEDs for each
>> band.  It's the full array of thousands of these that make up
>> the experience of hearing.
>>
>> Now since the Neurophone has no way single out individual
>> neurons and send just the right spike rate to each one, the
>> best it can do is fire a whole bunch of neurons together.
>>
>> Think of the task as playing the piano: Normal hearing has
>> way more than 88 "keys", but that will do for an example.
>> To get a melody, you have to press down different keys
>> at different times.  But the Neurophone can only press
>> *all* the keys or no keys, it can't single out specific keys
>> at specific times.  So lay a board across the piano
>> keys and try hitting it in the center with a hammer.
>> You can convey *information* this way, but not a melody.
>> In the same way, a single-channel stimulation system can
>> not convey speech or music to the brain.
>>
>> Best regards,
>>
>>
>
> Have you ever actually experimented with one? 

No, nor do I feel the need to.  Since I have relatively normal
hearing, any experiment would not address the question of
whether it is stimulating the nerves directly.  If I heard
anything (which I am not doubting) then it would be due
to some electroacoustic effect that produces true mechanical
vibration that is picked up by the cochlea and processed
by normal hearing mechanisms.  Any claims of direct
neural stimulation would be pretty hard to prove.

Think about the fact that cochlear implants *do* have
the ability to deliver a signal very close to the proper target
neurons.  In fact, they can deliver multiple different signals.
Yet they are still a ways away from recreating normal hearing.

So why should you believe anecdotal evidence from someone
with a vested commerical interest in selling a snake oil product?
If the neurophone actually worked on deaf people, why would
*anyone* go through the expense (and difficult training period)
of getting a cochlear implant?  And even assuming that somehow
the nerophone "inventor" was a hidden genius, or even if he just
got lucky, and made a startling scientific breakthrough, then 
why would the rest of the true hearing research community 
not pursue such a breakthrough? 

Or is this like the old tales of the "genius" with a supposed
miracle gas additive, or carburetor, or energy source, that
is suppressed by the evil "establishment" scientists? 


Best regards,


Bob Masta
dqatechATdaqartaDOTcom
 
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