Re: AND THEN, JUST TRANSPLANT THE BRAIN... was Re: Headless frogs

Anders Sandberg (
21 Oct 1997 11:48:38 +0200

I would like to point at Greg Egan's short story "The Extra",
apropos this subject.

"den Otter" <> writes:

> Then again, the technology needed to perform a brain transplant
> could probably also cure at least *some* of the (brain)diseases mentioned
> above. Any doctor in the house to verify this?

I don't see how it would help. Maybe it would be useful for people
with cardiovascular problems, but the strain of the actual transplantation
is likely large. Brain transplants might be useful for diseases of the
rest of the body, but suitable diseases are getting less and less common.

> > Another downside is the need to wait 18
> > to 20 odd years for any clone bodies grown _right now_ to reach any
> > reasonable form of physical maturity.
> I've once heard on some Discovery Channel program that you could
> grow (human) tissues at an astronomical rate under the right conditions.
> A small patch of cells could fill the floor of a football stadium in a
> matter of weeks or so, if cultivated under the right conditions.
> At least _some_
> organs could be grown in vitro on a skeleton of some kind of stuff that
> dissolves with time, maybe even whole bodies. This would only take
> a month or so(?).

No. You are right in that cells can divide very quickly in culture,
skin cells (which was likely what they discussed) breed like bacteria
under the right circumstances. The problem is that they do not form
differentiated tissue, just a thin layer of cells. What you would need
is a way to get the tissue to differentiate into an useful organ or
even a body, and that requires solving some rather tricky
problems. Most of the structure is organized by interactions of
diffusing morphogenic messenger molecules, activating or deactivating
genetic switches. Their rate of diffusion is *crucial* for the correct
organization, so you cannot speed up the formation of the body without
speeding up *all* diffusion coefficients. Tricky, very tricky,
bordering on the physically unlikely.

> > Talk about an industry, though-- the care and feeding of decerebrated
> > clones. How much per day do you figure it would cost to care for a
> > decerebrated clone? To make sure it is properly fed by whatever >means?
> > Can't have a clone come out of the tank malnourished.

To develop the body fully, you need some activity in the physical
world, not just a clone-tank. But to answer your question, it would
likely be very, very expensive. Tissue engineering is likely the way
to go, keeping spare clones around would be uneconomical.

Anders Sandberg                                      Towards Ascension!                  
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y