X-Message-Number: 19324
From: "Ben Best" <>
Subject: Brain electrical activity and personal identity 
Date: Fri, 21 Jun 2002 03:35:47 -0700

"Toby Christensen" <> wrote:

 > As you are well aware, when a person dies the electrical
 > activity in their brain ceases. What method do you see as
 > being able to "start up" a person's brain once their
 > freezing/mortal wounds etc. have been fixed?

    Other have commented on this point, but I want to add my
two cents -- some repetition but some forceful addition, I hope.

    I have already addressed the question in my essay
"Cryonics: The Issues", which is on my website at:


   There I say:

> Some people worry that the cessation of electrical 
> activity during cryopreservation would mean a loss 
> of personal identity & memory. Although immediate 
>(short-term) memories would probably be lost, there is 
> ample reason to believe that identity & long-term 
> memory is encoded in synapses and in the connections 
> between neurons -- which would be cryopreserved. Dogs
> have been cooled to low temperature in a bloodless 
> state with no evident electrical activity, yet
> have demonstrated memory upon recovery. Similarly, 
> humans reduced to a state of no detectable electrical
> activity by drugs have demonstrated recovery of 
> memory & identity.

    Someone has criticized my view by questioning the experimental
evidence in saying that just because no electrical activity has
been detected does not mean that no electrical activity existed.
This person clearly believes
that identity and memory lies in the electical activity itself
-- as if the electricity itself is a kind of "life". But if you
light a candle, the nature of the flame is a product of the nature
of the wax and the wick -- snuff the 
candle. Re-light the candle and the flame will be the same. 

    Similarly, if the heart stops and is restarted 
(and has not been damaged) the heart will resume operation, contracting
in response to the waves of electrical impulses in precisely
the same manner as it did before and 
producing the exact same result because the patterns of electrical
activity and the effects of electrical activity are entirely
determined by the structure of the fibers carrying the electrical
impulses and their connections. 

   Likewise, if the axons, dendrites and synapses -- including
the strength of synaptic connections -- in the brain are not
destroyed, then memory and personal identity should be maintained.
There is ample evidence that memory
is encoded by modification of synaptic strengths -- although
the physical connections by the cables (axons and dendrites)
are obviously an important part of this. Thus, re-starting the
electical signals should re-activate 
our memories. Obviously we do are not remembering 
every piece of knowledge in our brains at every moment
of our lives. What we are remembering at any particular
moment is a function of which neurons & synapses are being
activated at that moment. 

    During non-REM (non-dreaming) portions of our sleep-cycle
there is diminished electrical activity of the brain due to reduced
input from the reticular activating system (RAS). The RAS is
analogous to the pacemaker of the heart --generating electrical
signals to activate brain function, 
just as the heart pacemaker generates electrical signals to activate
heart function. To repeat, what those functions are depend upon
the connections in the heart & brain, not the instigation of
signals. The RAS is even less active in unconsciousness and coma
-- and if coma is deep enough 
there may not even be enough electrical activity in the medulla
to keep the heart functioning, much less the brain, and death
will ensue. To imagine that the RAS is a source of identity is
to confuse the nature of consciousness with the distinction between
being conscious or unconsious. 

    It is a property of the cells in the pacemaker of
the heart that they initiate electrical depolarizations
at regular intervals. I believe that the cells in the 
RAS have a similar inherent tendency to self-initiated
electrical depolarization. Thus, restoring the health
and functionality of RAS cells should restore the 
electrical activity of the brain. And restoring the 
neurons, synapses, axons, dendrites and the supporting
glia in the cerebral cortex, basal ganglia, etc., should
restore the critical features of consciousness -- memory
and personal identity. 

                       -- Ben Best

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