X-Message-Number: 26102 From: Date: Thu, 28 Apr 2005 07:10:17 EDT Subject: Re: CryoNet #26090 To T. Donaldson You said: > > A discussion of just how your system will simulate a brain, too, would > be useful here. I have pointed out that unlike what people thought only > 15 years ago, our brains are biologically active, growing new neurons > and new connections between old neurons. How do you propose to implement > this growth feature? This question becomes particularly important > because such growth apparently plays a role in learning and the formation > of new memories. I have mostly analysed the mathematical tools we can use to model the neuron up to now. My feeling is that the most important elements are there, I think most memory for example comes from the dendrite spine density on the dendrite tree. They give a weight to the synaptic spine well beyond what is possible with presynaptic potential action on vesicle release. I'll post in some days the 3.iii.0 message about how neurons can be linked in a neural network, there is a small preview: When a neuron, say X1, produces an action potential, it broadcast its address to a buffer. This one has a table telling what are the destination for X1 message, For example Y1, Z15, and so on. Y1 could be on the same chip but simulated 9 simulation blocks later, so the X1 signal will be loaded in this table. Z15 could be 18 simulation block later on another chip, so the X1 address would be sent to the buffer managing Z15. At each start of a simulation block, the table with all the entries addresses is sent to the FPGA so that the neurons get their input. My estimate is that current FPGA can simulate someting between 100 and 1,000 neurons at the same time and can use time sharing to look at 150 successive blocks. There could be so 150,000 neurons on a chip. Buffers chip would be linked in a network similar to Internet. So the brain could grow up to the addressing limit of the IP system. Yvan Bozzonetti. Content-Type: text/html; charset="US-ASCII" [ AUTOMATICALLY SKIPPING HTML ENCODING! ] Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=26102