X-Message-Number: 3902
Date: Fri, 24 Feb 1995 22:12:08 -0800
From: John K Clark <>
Subject: SCI.CRYONICS Uploading

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 (Eli Brandt)  Wrote:

	      >If the simplest part of the brain is, as postulated, an
	      >N-state device, then... that is the simplest part of the brain.
	      
You can postulate that 2+2 =5 if you like but that doesn't make it true.
	  
	     >You're saying that it's equivalent to a bunch of 2-state
	     >devices, and going from there to claiming that it actually is
	     >that bunch of devices. 
	     
Parts always treat other parts as black boxes or they wouldn't
be separate parts they'd be subparts of the same part. How a
black box does something is not important to other components,
what a black box does is important to other components.   
	     
	   >They're good enough over the span of a small dendritic tree. 
	   >Passive transmission *does* happen in the brain.
	   
I never said it didn't, only that it's slow and short range.
Incidentally "good enough" is evolution's motto not "perfection".
	   
	   > In fact, it's the predominant sort of dendritic transmission. 
	  
That of course is the standard view , recently however suspicion
has mounted that certain neurons may have active transmission
even in their dendrites because passive transmission is just too
slow for some things. 
	  
	 >I think this isomorphism/identity issue needs to be addresses
	 >if this discussion is to go anywhere.
	 
That's what I've been doing for the last 2 months so I'd rather
not repeat everything I said in my last 40 posts, but if
there's something new you'd like to add, be my guest.
	 
	 >the gap junction.  This is not a gated channel at all; it's a
	 >direct ionic coupling.  As such, it's much faster than an            
	 >electrochemical synapse,
	 
Yes, it's much faster than a chemical synapses, but still a LOT
slower than electronics because it doesn't use electrons it uses
ions and in this case some of them are big, very big, up to 1500
AMU. One AMU is as massive as 1822 electrons. Something that
heavy isn't going anyplace in much of a hurry. Also, the gap in
a gap junction is 2 to 4 nanometers wide, depending on the
neuron that's between a millionth and a billionth it's total length.
	      
	 >but doesn't do much information processing.
	      
I agree, their function can't be subtly adjusted as chemical
synapses can be. It's not even clear that all neurons have
connexons and so form gap junctions.
	 
	 >Conduction in salt water isn't light-speed fast, but I fail
	 >to see how you're going to speed it up much.
	 
By junking salt water and their overweight ions and moving to
electronics with their fast light electrons. It doesn't matter
how a neuron process and transmits information internally if you
treat neurons as black boxes, neurons treat their neighbors that
way in the brain so we can too. Their is no reason that
electrons can't produce the same input output relationship that
ions do and do it astronomically faster.

				John K Clark             

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