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That's starting to be figured out finally. They've identified the motor neurons and some of the ones involved with touch so that a simulated worm can actually

That's starting to be figured out finally. They've identified the motor neurons and some of the ones involved with touch so that a simulated worm can actually navigate around. I find it incredible though all this is done with as few neurons as it has (302). I've got everything downloaded and have been wanting to play with it in a simulation of some kind.

sanxiyn 12y ago
C. elegans neurons are non-spiking, making them more like analog circuits than digital circuits. In comparison, all mammalian brains use spiking neurons.
- simcop2387 12y ago
  Interesting, I always wondered if there were differences like that. The way I'd think of that if I were translating it to circuitry would be to say that the mammalian brains operate at saturation of a transistor (fully on, or fully off). And that C. elegans would then be operating in the linear region of the transistor; assuming that you could represent each neuron as a transistor of course. I wonder if the change in structure happened roughly for the same reason that we're changing much of our circuitry from analog to digital (or at least avoiding analog as much as possible) because we can get better noise response and simpler circuit design. Makes me wonder then if something like epilepsy could be caused by some neurons operating the wrong way and not giving clear signals down the chain which could lead to feedback and/or noise that ends up detrimental.
- delucain 12y ago
  Does this mean that one neuron can carry a signal that is more dense in data than a 0/1 binary spiking signal? Like a single neuron can transmit a complex feeling instead of just if it's touching something or not?
  - jacquesm 12y ago
    It can transmit continuous variable state rather than discrete state in pulses. Of course you can still transmit continuous variable state indirectly using pulses (for instance, using pulse width modulation or frequency modulation) but it requires a bit more hardware. Probably there is some kind of cross-over in complexity of the neural structure (density, length of the individual neurons) where it makes more sense to switch to a digital mode (cross talk for instance).

sanxiyn 12y ago

C. elegans neurons are non-spiking, making them more like analog circuits than digital circuits. In comparison, all mammalian brains use spiking neurons.

simcop2387 12y ago
Interesting, I always wondered if there were differences like that. The way I'd think of that if I were translating it to circuitry would be to say that the mammalian brains operate at saturation of a transistor (fully on, or fully off). And that C. elegans would then be operating in the linear region of the transistor; assuming that you could represent each neuron as a transistor of course. I wonder if the change in structure happened roughly for the same reason that we're changing much of our circuitry from analog to digital (or at least avoiding analog as much as possible) because we can get better noise response and simpler circuit design. Makes me wonder then if something like epilepsy could be caused by some neurons operating the wrong way and not giving clear signals down the chain which could lead to feedback and/or noise that ends up detrimental.
delucain 12y ago
Does this mean that one neuron can carry a signal that is more dense in data than a 0/1 binary spiking signal? Like a single neuron can transmit a complex feeling instead of just if it's touching something or not?
- jacquesm 12y ago
  It can transmit continuous variable state rather than discrete state in pulses. Of course you can still transmit continuous variable state indirectly using pulses (for instance, using pulse width modulation or frequency modulation) but it requires a bit more hardware. Probably there is some kind of cross-over in complexity of the neural structure (density, length of the individual neurons) where it makes more sense to switch to a digital mode (cross talk for instance).