X-Message-Number: 8525 From: Anders Sandberg <> Newsgroups: sci.cryonics Subject: Re: Memories Date: 02 Sep 1997 16:15:26 +0200 Message-ID: <> References: <> <> writes: > If it is true that memories are chemicals, then when you die, these > chemicals should disintegrate. That means all your memories - of who you > ARE, will be lost. This is likely wrong. Current neuroscientific opinion is that long-term memory is based on structural changes in the brain, not chemicals. Short-term memories are likely electrochemical in nature, and would disintegrate if there was time for chemical degradation (the critical period might be on the order of tens of minutes, judging from LTP data and reports of people revived after near-drowning). These short-term memories are then gradually consolidated into long term memory through at present little known processes, but the result seems to be changes in synaptic shape, size and number which are permanent. So if cryonics can preserve the synapses (and the connectivity of the brain) long-term memories ought to be preserved. Short-term memories will likely disappear, but a limited amnesia of the events just before being suspended is a small price to pay if the process works. The electron microscope photos of cryopreserved brain tissue that Mike Darwin showed me when I visited him suggested that the synapses were well preserved, but there might be trouble with preserving connectivity with present methods. Two references: Dyson SE, Jones DG: Synaptic remodelling during development and maturation: Junction differentation and splitting as a mechanism for modifying connectivity. Dev Brain Res 1984;13;125-137 Greenough WT, Bailey CH: The anatomy of memory: Convergence of results across a diversity of tests. Trends Neurol Sci 1988;11;142-147 I just noticed there is some relevant information in the FAQ too, at http://www.cs.cmu.edu/afs/cs/user/tsf/Public-Mail/cryonics/html/0018.2.html#2-7 -- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! http://www.nada.kth.se/~nv91-asa/main.html GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=8525