X-Message-Number: 19025 Date: Mon, 06 May 2002 10:09:22 -0700 From: Dave Shipman <> Subject: Re: Electrical activity and death This is a multi-part message in MIME format. --Boundary_(ID_tmGMnjScmI5SHNjduo2Mtw) Content-type: text/plain; charset=Windows-1252 Content-transfer-encoding: 7BIT 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 --Boundary_(ID_tmGMnjScmI5SHNjduo2Mtw) Content-type: text/html; charset=Windows-1252 [ AUTOMATICALLY SKIPPING HTML ENCODING! ] Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=19025