X-Message-Number: 5178 From: (John K Clark) Newsgroups: sci.cryonics Subject: Beyond 2000 and Mind Uploading Date: 14 Nov 1995 03:38:54 GMT Message-ID: <48930e$> -----BEGIN PGP SIGNED MESSAGE----- First of all I want to thank Brian Wowk for answering my questions about MRI. >>John K Clark >>My suspicion ( and I admit it's only a suspicion) is that >>a 1 nanometer resolution would be far more than what you >>would need for uploading, a resolution of a hundred, perhaps >>a thousand times less might be sufficient. >Brian Wowk >I don't see how. Neural anatomy (connection information) isn't >enough. Don't you need *chemical* (i.e. molecular) information from >the synapses? You could be right, on the other hand, it could turn out that chemical information is involved in short term memory and in the FORMATION of long term memory BUT that the memory itself is encoded in the gross anatomy of the synapses. I don't claim that this has been proven, but it is true that the most important storage mechanism is thought by most to be Long Term Potentiation ( LTP). It theorizes that memory is encoded by varying the strength of the 10^14 synapses that connect the 10^11 neurons in the human brain. It had been thought that LTP could be specified to a single synapse so each synapse was equivalent to one computer bit, perhaps several bits, but now it looks like that is a vast overstatement. In the January 28 1994 issue of Science Dan Madison and Erin Schuman report that LTP spreads out ( the LTP signal is probably sent by the diffusion of nitric oxide) to a large number of synapses on many different neurons. The individual synapse cannot be the computer bit of the brain. Neural Net expert Terrence Sejnowski commented on these new findings " Instead of thinking of a synapse as representing a piece of information you can now begin thinking of a population of potentiated synapses acting together". All this severely reduces the storage capacity of the brain but increases it's redundancy. This is good news if we want to repair a badly damaged frozen brain. Also, although it may hurt our pride to think that our essence can be defined with less information than we thought, it also means that uploading will be easier ; there's less you need to upload. It's not obvious to me that we must need an astronomical amount of long term memory in order to function. I've heard that some medical specialists were distressed to find that AI programs of just a few megabytes could make pretty good diagnoses in their field. Considering the years it took them to acquire this knowledge, they expected that a much larger program would be needed. John K Clark -----BEGIN PGP SIGNATURE----- Version: 2.6.i iQCzAgUBMKgM4303wfSpid95AQFipATsDfwRhte/5U6ubLVAuvPjiIvnHPx0h4nJ ofRz+55MyqQjnd6xDV0M8MgHj51qkehSHU5jjNRPbh4duewvSAsAj80mv8yY3CTa /Y2L+t0V/SdAzMC2oyh7XnmtaIL2PJ36uKiY6EHdtSRMQlZAmkz3TRtEAxdfJCZG S6SQH1twQiiTf5qkXM6j60da81tbSJf36nhCx/mHEQkLxzmWCUE= =A2RR -----END PGP SIGNATURE----- Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=5178