[MURG] RFC - necessary neuron info

[Joseph J. Strout]

At 6:32 PM +0200 10/8/03, Eugen Leitl wrote:

>  > Well, in general, anything that changes on the timescale of minutes
>>  or hours is probably not essential; loss of that should at worst
>>  produce a small retrograde amnesia (which is quite common, e.g. due
>>  to head trauma or anaesthesia, and poses no problems for survival).
>
>Considering the amount of structural information erasure occuring with a
>typical cryonics patient, we're talking about one hell of a retrograde
>amnesia.

I never said anything about a typical cryonics patient.  We seem to 
have skipped topics here.  The context of my text you quoted above 
was, what sort of information do we need to capture for a successful 
upload.

I do understand that successful cryonic preservation is nontrivial, 
and I'm hoping that the state of art will continue to improve before 
I need it myself. :)

>  > emulation to default states, turn it on, and let itrun -- this
>>  certainly will be a much smoother startup process than, say,
>>  recovering from a seizure.
>
>CNS activity attractors emerge very nicely from system noise. If we can't
>simulate that very basic, trivial function we can as well go home now.

Yes, that's a good way to put it.

>Gene networks of course have a state and of course have a very definite
>external activity (see embryomorphogenesis for an illustration what the cells
>can actually do). These are of course not magic, and can be parametrized.
>However, for time being we're looking at the lowest feasible level of theory
>simulation imaginable, so we know where the cutoff is, and where
>we can start parametrizing. Everything else is completely ad hoc.

I'm not quite sure I follow your point here.  I'm thinking about what 
sort of scanning technologies are required.  Apart from the 
possibility of gene activation, I think everything we need could be 
captured by, say, serial-section EM (electron microscopy).  But if 
gene activation is something we can't ignore or infer from 
morphology, then EM won't cut it, and we'll need to use something far 
more exotic.

>  > It's possible that there will be genes which are
>>  activated/deactivated as an important part of the information-storage
>>  process, but which do not manifest in any more obvious phenotype.
>
>I think that's a safe bet. Even if they result in phenotype change, the
>simplest way to generate a phenotype change is to model the gene activity
>network.

I'm hoping it's not a safe bet.  But as for your second statement, 
you seem to be thinking about the modeling; I'm thinking about the 
data capture.  If we can infer gene activation state from phenotype 
(morphology in particular), then great!  Let's do that.  If not, then 
we need to come up with a way to determine gene activation state of 
individual cells in cold, sectioned tissue.

>You're rather optimistic here, but it might be true. Right now we're lacking
>data to even calibrate the model. Both in vivo imaging and activity recording
>are at their infancy.

Yes, I recognize that this is the biggest instance of hopeful 
thinking in the whole plan.  And it may not turn out to be true.  In 
that case, I do believe there are ways to tackle it; it's just going 
to be a lot harder.

Cheers,
- Joe

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