Received: by alpheratz.cpm.aca.mmu.ac.uk id QAA28020 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Tue, 7 Mar 2000 16:29:49 GMT To: memetics@mmu.ac.uk Date: Tue, 07 Mar 2000 08:27:22 -0800 From: "Scott Chase" <hemidactylus@my-Deja.com> Message-ID: <GDLFJBPEOIDMDCAA@my-deja.com> X-Sent-Mail: off X-Expiredinmiddle: true X-Mailer: MailCity Service Subject: Re: Cherkin on the mnemons X-Sender-Ip: 209.240.200.104 Organization: My Deja Email (http://www.my-deja.com:80) Content-Type: text/plain; charset=us-ascii Content-Language: en Content-Length: 3140 Content-Transfer-Encoding: 7bit Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk
--On Tue, 07 Mar 2000 10:36:08 Mark M. Mills wrote: >Scott, > >At 04:48 PM 3/6/00 -0800, you wrote: >>He applies "mnemon" to an anatomical unit of memory, viz., a module >comprising an >>activated classifying neuron and its closely associated cells. This >specific application >>of "mnemon" is compatible with the general definition proposed in this >article." (eq) > >Koch's 'Biophysics of Computation' doesn't use the term 'mnemon.' Instead, >he reviews 13 different physical mechanisms for memory instantiation. As >best I can tell, the fundamental building block would be called a 'receptor.' > >In Kock's view, there is the substrate of neural chemistry and the flow of >binary signals across it. Koch describes neural abilities in terms of >'bits per second' transmission speeds. Every neural cell can be seen as an >independent computer, constantly making its own decisions, constantly >processing internal and external signals, constantly transmitting signals. >Just as in computers, there is the data in the 'bit stream' >(electromagnetic waves) and static electrical states recorded on physical >media (short term and long term memory). > >The fastest physical media for memory storage which Koch describes is >autophosphorylating kinases. These reside on synapse membranes. They are >electrical gates and can flip from 'open' to 'shut' in less than a 1000th >of a second. > With regards to LTP there are several putative paths and components. I'm not familiar with Koch (or formal neurocomputation), but you might be interested in a couple articles which focused on an autophosphorylating kinase. I'm rusty on this subject and need to get back into the literature on NMDA-R, calcium calmodulin kinases, and even some molecular angles of synaptic plasticity, memory, and learning which I never touched on before, except at a very shallow level (eg- NO and retrograde transmission). I had a decent critique/review paper on LTP, but I can't find it at present. As I recall there's some controversy over what exactly LTP research is aiming at. The parallels with the Hebbian synapse (stemming from properties of the NMDA receptor) are kinda cool.
See (for the calcium calmodulin kinase stuff):
Silva AJ, Stevens CF, Tonegawa S, Wang Y. 1992. Deficient hippocampal long-term potentiation in alpha-calcium-calmodulin kinase II mutant mice. Science (257): 201-206
Geise KP, Fedorov NB, Filipkowski RK, Silva AJ. 1998. Autophosphorylation at Thr-286 of the alpha calcium-calmodulin kinase II in LTP and learning. Science (279): 870-873 > >Do you think the mnemon term makes sense when signal processing concepts >seem most appropriate for study of neural function? > > There should be a term for a memory trace or memory unit. I'm mostly interested in the history of this right now. There are things I'm compelled to say, but I'm several months to a year removed from my readings on several topics, so I don't want to put my foot in my mouth without double checking.
Scott
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