You would have to replicate then not only the dynamics of neurons, but
every biomolecule in the neurons, and don't forget about the
oligoastrocytes and other glial cells. Many enzymes for instance to
multi-state systems, say in a simple case where a single amino acid residue
of phosphorylated or unphosphorylated, and in effect are binary switching
units. To then make this work you now need to have the brain states mapped
out down to the molecular level, and further to have their combinatorial
relationships mapped. Biomolecules also behave in water, so you have to
model all the water molecules. Given the brain has around 10^{25} or a few
moles of molecules the number of possible combinations might be on the
order of 10^{10^{25}} this is a daunting task. Also your computer has to
accurately encode the dynamics of molecules -- down to the quantum
mechanics of their bonds.
This is another way of saying that biological systems, even that of a basic
prokaryote, are beyond our current abilities to simulate. You can't just
hand wave away the enormous problems with just simulating a bacillus, let
alone something like the brain. Now of course one can do some simulations
to learn about the brain in a model system, but this is far from mapping a
brain and its conscious state into a computer.
LC
On Saturday, March 31, 2018 at 10:31:56 AM UTC-6, John Clark wrote:
>
> On Tue, Mar 27, 2018 at 8:24 PM, Lawrence Crowell <
> [email protected] <javascript:>> wrote:
>
> > *Yes, and if you replace the entire brain with technology the peg leg
>> is expanded into an entire Pinocchio. Would the really be conscious? It is
>> the case as well that so much of our mental processing does involve hormone
>> reception and a range of other data inputs from other receptors and
>> ligands.*
>
> I see nothing sacred in hormones, I don't see the slightest reason why
> they or any neurotransmitter would be especially difficult to simulate
> through computation, because chemical messengers are not a sign of
> sophisticated design on nature's part, rather it's an example of
> Evolution's bungling. If you need to inhibit a nearby neuron there are
> better ways of sending that signal then launching a GABA molecule like a
> message in a bottle thrown into the sea and waiting ages for it to diffuse
> to its random target.
>
> I'm not interested in chemicals only the information they contain, I want
> the information to get transmitted from cell to cell by the best method and
> so I would not send smoke signals if I had a fiber optic cable. The
> information content in each molecular message must be tiny, just a few bits
> because only about 60 neurotransmitters such as acetylcholine,
> norepinephrine and GABA are known, even if the true number is 100 times
> greater (or a million times for that matter) the information content ofeach
> signal must be tiny. Also, for the long range stuff, exactly which neuron
> receives the signal can not be specified because it relies on a random
> process, diffusion. The fact that it's slow as molasses in February does
> not add to its charm.
> If your job is delivering packages and all the packages are very small and
> your boss doesn't care who you give them to as long as it's on the correct
> continent and you have until the next ice age to get the work done, then
> you don't have a very difficult profession. I see no reason why simulating
> that anachronism would present the slightest difficulty. Artificial
> neurons could be made to release neurotransmitters as inefficiently as
> natural ones if anybody really wanted to, but it would be pointless when
> there are much faster ways.
>
> Electronics is inherently fast because its electrical signals are sent by
> fast light electrons. The brain also uses some electrical signals, but it
> doesn't use electrons, it uses ions to send signals, the most important are
> chlorine and potassium. A chlorine ion is 65 thousand times as heavy as an
> electron, a potassium ion is even heavier, if you want to talk about gap
> junctions, the ions they use are millions of times more massive than
> electrons. There is no way to get around it, according to the fundamental
> laws of physics, something that has a large mass will be slow, very, very,
> slow.
>
> The great strength biology has over present day electronics is in the
> ability of one neuron to make thousands of connections of various strengths
> with other neurons. However, I see absolutely nothing in the fundamental
> laws of physics that prevents nano machines from doing the same thing, or
> better and MUCH faster.
>
> John K Clark
>
>
>>
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