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Richard Piotter, "[alt-beam] Nu interconnections (from MWT himself!!!)", 31 Mar 1999 http://groups.yahoo.com/group/alt-beam/message/1904 This was from Mark Tilden (sent back on March 9th). Mark W. Tilden wrote: > I've been wanting to do a lot of new
work with Nu/Nv circuits. I've > read on the BEAM tech FAQ how to make
"sensory" Nu neurons, however, > in the Living Machines paper, there
are interconnected Nu units that > have bidirectional connections between
each other and are > in "contact" with Nv
neurons. I'm very curious how these neurons are > interconnected between each other.
I've looked and can find little > information other than the individual
units, but no information on > how they connect between each other.
Do you have any papers with > more detailed examples of such circuits? I'm familiar with Lobster's
> structure, but as I said, there are many questions.
Hey Richard. Good to hear from you. Lobster was an attempt at putting an Nv ring inside a homogeneous Nu ring, where the outputs of the Nu+'s feed trough a resistor into the bias input of an Nv. At the time, I thought I was making direct "learning Nv's" by this coupled association. However, it failed because the responsiveness of the Nv's was far higher than that of the Nu's, so at higher process numbers the adaptive benefits of the Nu network just cut out or became detrimental. Another lesson of the difficulty in making reactive-adaptive devices, Lobster was and is a really good "bad" example of autonomous control hierarchy. That's why I never published further details on it. That diagram is also embarrassing, as the lexicon for describing Nv nets has advanced significantly over the years. A more appropriate and accurate picture would be as follows: | R0 | --- _|_ /Nu+\____R1__|/Nv-\ \___/ |\___/ --- /|\ | | |R2 | | | ___ | --- _|_ /Nu-\ /Nv-\ \___/ \___/ --- /|\ |R3 |
Where plates indicate an implied or resistive connection, and arrows the connections between Nv outputs and the capacitor inputs of the subsequent neuron (the "primary axon"). > ...It appears neurons have plain lines
(presumably the output), and > it has tries and circles on other
lines. Some neurons (only a few) > are in contact, much like the Nu and
Nv pairs on Lobster. If you can > 1, tell me if there is some sort of
standard, as to what the symbols > mean (excitatory or inhibitory
presumably), then that'd be > appreciated. Second, the neurons in
this network seem to have both > excitatory and inhibitory inputs. Is
it possible to recreate this in > BEAM technology? ___ / \----------o\___/ ` `-----
Yes. Circles are excitory, triangles are inhibitory, and wires are dendrite outputs, by neurobiological convention. The behavior of a brain cell is very much like the basic solar engine with multiple valued resistors feeding onto the PNP base junction. Generally, when the neuron has reached it's "presynaptic threshold" (gets a charge), a small excess stimulus on the membrane wall will result in a one-shot spike or spike-sequence from the neuron amplifier. In biology, inputs are sparsely valued, and can in fact be pre-empted as in the following example. \ | \-- Where the excitory effect of a dendrite is inhibited on the dendrite itself by several inhibitory junctions. This discovery has led to the new trend of analyzing the dendrites for processing abilities in the brain, not just the neurons. The "dendritic processing model" as it's called is one of the newest fields in neurobiological research, and it's a bitch because of the four additional orders of complexity it involves. You must also realize that the "plain line" of a dendrite or axon is anything like an electric wire. It is a carefully regulated tube through which a calcium wave passes like a bubble through a straw. As such, when it is amplified or inhibited, it really is a physical speeding, expanding, or slowing and shrinking of the wave signal. The electric field measured by EEGs and other things just monitor the electrical side effect of what is primarily a chemical reaction in our heads. Biomech tech is thus different but related. How is controversial because of the many academic egos involved, but I say if the neuron works... Nv systems that use Schmitt triggers are different from real biological neuron processes as they are threshold symmetric: that is, you can make +ve or -ve biased Nv networks and they'll still behave the same, just inverted. In biology there is no choice but to use the one type of grounded neuron. The power of advanced Nv systems takes advantage of the fact that the symmetric sum bias of an Nv determines its polarity, and thus it's phase and interaction with surrounding Nvs. "Excitory" and "Inhibitory" thus mean different things in symmetric networks as their operation completely switches based upon what that particular Nv is doing at the moment. Unfortunately, currently there is no simple circuit that can show this without significant hand-convergence of parameters and robot morphology. Every year I test my new circuits on the "small gods" at our conference, and if they don't get it, well there's just no point in publishing. I get enough "is my solar engine resistor in the right way round?" emails as it is. You can wait for my book (getting fatter all the time), or better yet, make the discoveries it seems you're well on your way to finding. Don't forget, BEAM is the educational branch, but if you're into application, then biomech tech is what we call Nv Engineering. > Also, where is the next BEAM games
going to be held?
Sorry, I've been meaning to update the mailout. Next small workshop is scheduled for Los Alamos NM first full week in April. Availability is limited. Contact Paul Argo (pargo@lanl.gov) for details. As well, the next Olympics are scheduled for Santa Fe NM next summer 2000, details pending. Happy botting. markt. |