X-Message-Number: 19025
Date: Mon, 06 May 2002 10:09:22 -0700
From: Dave Shipman <>
Subject: Re: Electrical activity and death

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In response to Toby Christensen's query in CryoNet #19021:

>> Upon death, the brain's electrical activity ceases.

This is true.

>> All information is lost when brain activity ceases, as the electrons
which constitute brain activity disperse.

This part is false however. So far as we know, the information in the
brain is stored in its physical neurological structures. While there is
electro-chemical activity when the brain is functioning, the movement of
ions and neurotransmitters does not in itself constitute long-term
stored information but rather corresponds to the processing of that
information. The situation is similar to a computer's hard drive. The
information on the disk is not lost when the computer is turned off.

In particular, we know this is true for the brain because in many cases
of open heart surgery, the patient's brain is cooled to minimize
ischemic damage (that is, damage from lack of oxygen to the tissues). By
cooling the brain in this way, metabolic rates are lowered and so also
are the cells' oxygen requirements. Here's the interesting part: While
cooled, the brain waves on the EEG display go flatline. There is no
measurable electrical activity. After the surgery, assuming all has gone
well, the patient suffers no loss of memory, skills, personality, and so
on.

The same principle is important in cryonics. As soon as possible after
the legal pronouncement of death, the patient's temperature is lowered
as quickly as possible, but not below freezing. Again the principle is
to lower metabolic activity, reduce oxygen requirements and minimize
ischemic damage. In Alcor's protocol, oxygenated blood continues to be
circulated and appropriate medications are administered to support the
lowered cellular metabolism. The intent is to maintain neurological
structure until the brain and other tissues can be perfused with
cryoprotectant. At that point the cooldown to liquid nitrogen
temperatures can proceed. Hopefully, throughout this process the brain's
detailed neuronal structures are maintained, at least to a degree which
will allow future revival with memory and identity intact.

	-- Dave Shipman


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