01904 [alt-beam] Nu interconnections (from MWT himself!!!)

Alt-BEAM Archive

Message #01904

To: beam beam@corp.sgi.com
From: Richard Piotter richfile@rconnect.com
Date: Wed, 31 Mar 1999 00:30:31 -0600
Subject: [alt-beam] Nu interconnections (from MWT himself!!!)

This was from Mark Tilden (sent back on March 9th)

"Mark W. Tilden" wrote:
>
> >Hello. 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 indidual 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
> higherarchies. That's why I never published further details on it.
>
> That diagram is also embarassing as the lexicon for describing Nv nets has
> advanced significantly over the years. A more appopriate 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 axion").
>
> >...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
> dendritic outputs, by neurobiological convention. The behavior of a brain
> cell is very much like the basic solarengine 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 stimulis 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.
>
> > \ |
> > \--<|
> > \ |>-------
> > \ _o_
> > / \>-----
>
> 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 analysing 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 axion 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 acedemic egos
> involved, but i say if the neuron works...
>
> Nv systems that use Shmitt triggers are different from real biological
> neuron processes as they are threshold symetric: 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
> symettric 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 symetric 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 solarengine 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.

--

Richard Piotter
richfile@rconnect.com

The Richfiles Robotics & TI web page:
http://richfiles.calc.org

For the BEAM Robotics list:
BEAM Robotics Tek FAQ
http://people.ne.mediaone.net/bushbo/beam/FAQ.html

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