IUBio Biosequences .. Software .. Molbio soft .. Network News .. FTP

machine brains

Michael Edelman mje at mich.com
Tue Mar 9 10:20:02 EST 1999

Malcolm McMahon wrote:

> ...
> >
> >That would be very energy inefficient. Neurons don't grow at random. There needs to be some sort
> >of activity or chemical trigger.
> >
> It may be the only way to go. It is known that most young neurons which
> are produced during the growth of an embryo self-destruct.

Not self-destruct, but atrophy from disuse. You start out with a surplus of synapses and select. But
that's different from unregulated growth.

> ... The material from
> cells that suicide is available for other cells.

Mm. No. Generating and supporting cells is energy intensive. It requires energy to clean up dead
cells. The remains are excreted.

> >> >ECT typically affects LTM as well, and I don't think it's accurate to say it "completely
> >> >scrambles the electrical state of the brain". It doesn't scramble it at all- rather, it
> >> >synchronizes it, much as occurs in a seizure- which is where the idea for ECT came from.
> >>
> >> I think it's probably pretty much like when your PC locks up and you
> >> switch it off for long enough for the capaciters to discharge, then
> >> start it up again.
> >
> >Mm. Not quite.
> >
> >In a seizure, you get a situtaiton where a pattern begins in one area and radiates outward from
> >that area, with the activation spreading outwards until a large portion of the neurons are
> >firing in syncrhonization. This goes on until limited by depletion of neurotransmitters, lack of
> >oxygen or some other limiting activity.
> >
> Yup, but the effect is the same in that either will disrupt any volatile
> data in the system which will have to start with only non-volatile data.

You may be inferring too much from the computer metaphor. ECT disrupts LTM. The older the memory the
more resistant to loss, but that's probably a function of how integrated it is, not whether it's
electrical in nature.

> I'd speculate that certain pathological mental conditions might be the
> equivalent of a computer being stuck in a loop, or blocked by some kind
> of mutual lockout.

Again, I think you're delving into the realm of the metaphorical. There are psychopathologies that
can be described as self-reinforcing but that's feedback on a much more abstract level.

> >> I certainly don't dismiss its existance, only that it can be observed
> >> other than subjectively.
> >
> > So the quesiton is whether we can do science on conciousness. I think we can.
> We may be able to look at the interface between consciousness and the
> rest of the universe and learn a lot about how consciousness behaves.
> This doesn't necessarilly tell us anything about what consciousness is,
> though it might prove very usefull.

We can't examine QSOs or quarks, yet we can make reasonable deductions about their composition and
physics. So it is with conciousness.

> .....
> >> Rather, what it does is to deal with those that say that nothing
> >> constructed of known particles can exist.
> >
> >Are you taking a sort of vitalist stance here- that conciousness is a non-physical
> >substance? I'm not entirely clear as to your argument on this point.
> What I'm saying is that something can be physical, and real without
> being composed of material known to physics. This is, I guess, a
> vitalist position in some ways (though there's no proof that all life is
> conscious or that all consciousness exists in living things).

Once you say "physical" you're saying it has some sort of physical extension, which certainly puts
you in the vitalist camp. Why do you think this is the case?

> >> > And anyways,
> >> >conciousness is far too complex to compare it to an electron ;-)
> >>
> >> Now that's an interesting aspect. If you separate consciousness from
> >> mind, and ego then why does it need to be complex?

I don't. Conciousness is a property of mind.

> >
> >Re my earlier argument, which relies on a definition of complexity: How much
> >information does it take to describe? The amount of information needed to describe a
> >unique conciousness is far greater than that needed to describe a unique electron.
> >
> Not necessarilly because the detail you're talking about is the detail
> fo the ego, not of the conscious self.

 My conception is that ego  is an aspect of concious self.

Michael Edelman     http://www.mich.com/~mje

More information about the Neur-sci mailing list

Send comments to us at biosci-help [At] net.bio.net