X-Message-Number: 10410 Date: Fri, 11 Sep 1998 09:53:50 -0400 From: Thomas Donaldson <> Subject: CryoNet #10406 - #10408 HI everyone! I will assume that the micrographs produced by 21st Century Medicine and others looking at the brains of animals cryonically suspended were reasonably competent. However there is another issue and it is very important and absolutely MUST NOT be forgotten. Platt himself described the results as looking fine on gross examination, while the electron microscope showed lots of damage. It is now 1998, and whatever else has happened in neuroscience since the 1970's, it is now EXTREMELY likely that by one means or another our memories are shown (I won't say "encoded", since that introduces a bias I don't want) in the connections between our neurons. Put bluntly, this means that our memories may well continue to exist despite a great deal of damage to the individual neurons. The kind of damage which might destroy memory would be extensive loss of this connectivity, and connectivity occurs at a higher level than most cell functions. It also occurs on a level higher than that of molecules or atoms -- much higher. Such things as the biochemicals present in the damaged cells can be quite relevant, if we want to RECOVER connectivity which has somehow been broken. Electron micrographs aren't noted, unfortunately, for their ability to identify the biochemicals present and their distribution in the neurons and glial cells of our brain (or anywhere else, either). There is, however, quite extensive knowledge of how to produce stains which show up the presence of many different chemicals, individually. One major method for doing so is to use immune reactions to them to produce antibodies (say, you get a rat to produce an immune reaction to a human brain chemical). These antibodies are then chemically linked to a suitable fluorescent (or radioactive, or colored) chemical and the brain area is then soaked in them. Presto! You now know the distribution of the particular biochemical you wanted to study. A recent issue of PERIASTRON described how this method could distinguish between all the different interneurons (put simply, our brain cortex consists of pyramidal cells and interneurons --- its actually much more complex, but basically this is the situation) in our brain cortex. Since interneurons also have characteristic areas on the pyramidal cells to which they connect, this tells us where connections may have been. There are also older methods which simply use particular chemicals. These can show the presence of synapses (or their absence). Clearly some special methods would then be needed to somehow revive, repair, or replace (WITH their connections) the damaged neurons, and probably the damaged glial cells too. (Glial cells generally provide lots of metabolic support for the nerve cells, but don't directly contain information). That's where nanotechnology of some kind comes into the picture. This does not prove that our memories will necessarily survive. We won't have any idea of this until we do much more study. However it does say that ELECTRON MICROGRAPHS ALONE GIVE A QUITE LIMITED AND BIASED PICTURE OF THE STATE OF A DAMAGED BRAIN. It also says that repairing brains even on a molecular scale, while it may sound impressive, misses the MAJOR KIND OF DAMAGE completely. We can restore ourselves, with our memories, despite many rearrangements within each of our neurons --- such rearrangements are simply irrelevant to our memories, though within wide limits they do affect the survival of a particular neuron. (ie. just where the mitochondria may be isn't of much importance at all, so long as there ARE enough mitochondria working). So here are some thoughts about how brains work, and how that is VERY relevant to cryonics. Best and long long life to all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=10410