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Basic Neuron Questions

KP-PC k.p.collins at worldnet.att.net%remove%
Sun Apr 6 23:48:42 EST 2003


"BilZ0r" <BilZ0r at TAKETHISOUThotmail.com> wrote in message
news:Xns93566F2211F57BilZ0rhotmailcom at 202.20.93.13...
| "KP-PC" <k.p.collins at worldnet.att.net%remove%> wrote in
news:Ggwja.14342
| $cO3.997264 at bgtnsc04-news.ops.worldnet.att.net:
|
| > "BilZ0r" <BilZ0r at TAKETHISOUThotmail.com> wrote in message
| > news:Xns9354C35BBFAE7BilZ0rhotmailcom at 202.20.93.13...
| >| neo55592 at hotmail.com (Neo) wrote in
| > news:4b45d3ad.0304042219.2e905a42
| >| [...]
| >| The ABSOLUTE refractory period is between 4 and 5ms (the time it
| > takes
| >| for potassium channels to close).
| >
| > In vivo, no such "absolute" exists. Everything occurs relative to
| > ionic concentration gradients.
|
| Yes there is, Its defined by the time it takes for the potassium
channels
| to be available for opening again.

That this or that is "defined" to be tat or this does not make this
or that that or this.

The =only= "absolute" that exists within Living nervous systems is
that their functioning rigorously conforms to WDB2T.

The rest is dynamic as a function of experience. No neuron is ever in
the same 'state' twice because all neurons undergo microscopic
trophic modifications as a result of the activation that acctually
occurs within them, and the rest of the neural structure in which
they are embedded - all the way up to the nervous system as a whole.

Such feeds-back into the ionic concentration gradients which
determine the stuff that you were non-existent-ideal-case
short-shrifting, with the result that the 'ideal case' is total
fiction.

| > [...]
| > Within Living nervous systems, there exists
| > no such thing as "normal" levels of stimulation.
|
| What? Yes there are. look at any monosynaptic
| nevous pathway.

As above, there exists no such thing as a neuron whose energydynamics
occur as the sole result of synaptic 'events' - the synaptic
'events', themselves, occur as a function of whole-nervous-system
energydynamics.

If it were as you say, to the degree it were so, the 'nervous system'
in question would be a non-learning automaton.

| > [...]
| >| If we assume were dealing with a small,
| >| unmylinated neuron the AP propigates at about
| >| 5 meters a second, or 5mm a millisecond, so in
| > 4-5ms it travels 20-25mm, about a 10th of an inch.
| >
| > Can't say this without discussing the neural
| > architecture in which the neuron exists, and the
| > activation that's occurring within it - especially with
| > respect to unmyelinated neurons.
|
| What I can't say how fast a action potentialtravels?
| Lol. Not exactly, but I can give the accepted range.

It's like I said, OK at an introductory 'level', but totally useless
if one actually wants to comprehend how nervous systems work.
Clearly, if it's "bionet.neuroscience", we're beyond the former, and
interested in the latter.

| >| If were dealing with a large mylinated neuron,
| >| were talking 100-120meters a second, to
| >|100-120mm a millisecond, so in 4-5ms thats
| >| 400-600mm or about half a meter. (Someone
| >| correct me if my maths is wrong).
| >
| > Your conceptualizations are wrong.
|
| My 'conceptualizations' are just fine. I paraphrased
| my answer kandel and Schwatrz, principles of neural
| science 4th ed. Go argue with them. They're at the
| centre for neruobiology and behaviour. College of
| physicians & surgeons of Columbia University and
| the Howard huges medical institute. I've got no time
| for your bizzare one tracked mind.

I wondered what text you were ripping-off without giving credit.

I took the matter up with the source decades ago.

I stand on what I've posted. So do you. So does the source.

K. P. Collins





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