X-Message-Number: 11452 From: Thomas Donaldson <> Subject: To Jeff Davis, a very short summary of what we know about brains Date: Wed, 24 Mar 1999 23:28:19 +1100 (EST) Hi everyone! To Jeff Davis: Basically what you say is probably right. The major way in which memory is apparently stored in our brain is now believed by most neuroscientists to consist of the connections between neurons and the propensity of these connections to respond. And yes, some major brain structures important for brain FUNCTION may not be needed for the actual preservation of memory. The hippocampus and other nearby structures play an important role in at least one kind of memory, both for learning and for recall. But their preservation of memory, aside from a period of several days (with a gray area on just how long) is not involved in true long term memory ie. all the connections in other brain areas which form the permanent memory. This suggests that total loss of a hippocampus would not really affect storage of information, and by replacing those structures we would recover the person. But there are many other kinds of damage. Alzheimer's Disease ultimately destroys the brain cells generally (though it at first attacks particular areas). Ultimately the person becomes unrecoverable. Multiple small strokes can wipe out memory, though their exact effect depends on exactly where they occur. The structures which apparently contain memory of one kind or another SEEM to consist of the brain cortex generally and part of the cerebellum. I put together a bibliography on memory and how it works at the level of neurons and brains which I can send to you if you wish (by email). You will note that in this Cryonet, I have another message pointing out that nanotechnology will not solve all problems. To recover a damaged person (or alternatively show that they are irrecoverable) may well require some form of nanotechnology, both for the recovery and to investigate just what has happened. But for both purposes we will also need to know more than we do now about brain structure and activity, both for healthy brains and for damaged brains. And if you get REALLY interested, I publish a newsletter which discusses such things, in the special context of cryonics. Yes, the newsletter costs money while the bibliography is free. Best and long long life, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=11452