[extropy-chat] Scientists say nerves use sound, not electricity

[Anders Sandberg]

> --- Emlyn <emlynoregan at gmail.com> wrote:
>
>> Scientists say nerves use sound, not electricity
>>
> http://www.cbc.ca/technology/story/2007/03/09/science-nervessound-20070309.html#skip300x250
>>
>> ???

LOL! Back to Descartes' pneumatic nervous system!

Talk about throwing away the baby with the bathwater!

The Avantguardian wrote:
> I just read the primary article here:
>
> http://www.biophysj.org/cgi/rapidpdf/biophysj.106.099754v1

No, that is not it. That is a not too unreasonable take on anasthetic
action, not action potentials. Here is their theory:
http://arxiv.org/PS_cache/physics/pdf/0610/0610117.pdf

The paper is not bad, it is just that it sounds like physicists who have
not got much of a clue about neuroscience. They have what looks like a
genuine physical problem, the lack of dissipation during the action
potential, and immediately propose a solution, a density pulse causing the
action potential as a piezoelectric effect. The problem is that
neuroscientists know *a lot* about action potentials, including how to
block or modify them by blocking the ion channels. The soliton model would
predict that the ion channels don't matter! It also would seem to crash
for saltatory signals along myleinated axons (unless they claim the myelin
increases the speed of sound).

In fact, the only experimental support they cite is measurements of force
on a piston as an action potential passes, and membrane fluoroscence
changes. But to me the close similarity between the force curve and the
potential curve suggests that the piston might simply have become charged,
not that the membrane is bulging. And the fluoroscence is no evidence that
the membrane is actually moving, just that there is local conformational
change.

I think consciousness research (which this really is, given the strong
emphasis on anesthesia) is detrimental for the critical faculties of
researchers.

-- 
Anders Sandberg,
Oxford Uehiro Centre for Practical Ethics
Philosophy Faculty of Oxford University