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Map of an Insect’s Brain
121–128 of 128 posts
Re: Map of an Insect’s Brain
#122Earlier quoted context omitted.
> A fruit fly brain is a better model to simulate in this regard. It's much more "generic", so there's a hope that we can recapture high-level behavior from it more easily. This is a completely baseless assumption. It is also moot, since simulating even 300 neurons is beyond our current computational power; simulating 3000 is not going to be possible in the foreseeable future.
What makes stimulating 300 that computationally heavy? (Doesn't sound like many?, but I've read that one single neuron needed 100 or so nodes in a deep neural net to simulate. But 300*100 also doesn't sound like many (nodes)?) Edit: some explanations here: https://news.ycombinator.com/item?id=35113498 (in this discussion)
The problem is not the neural simulation, but that we need to simulate pretty much all of the worm. And we currently can't do that.
The neurons in worm directly interact with muscle cells, for example, via peptide/monoamine signalling. Or with "remote" neurons.
This is all possible because neural network of the worms is directly integrated with everything. And the connectivity is hard-coded in its genome.
It's not true for more complex organisms, simply because you can't encode that kind of complexity in DNA. Instead it encodes the overall connectivity structure, so that emergent behavior provides necessary instincts.
Re: Map of an Insect’s Brain
#123Earlier quoted context omitted.
What makes stimulating 300 that computationally heavy? (Doesn't sound like many?, but I've read that one single neuron needed 100 or so nodes in a deep neural net to simulate. But 300*100 also doesn't sound like many (nodes)?) Edit: some explanations here: https://news.ycombinator.com/item?id=35113498 (in this discussion)
Yep, pretty much that thread. Massively simplified models exist, and yeah - we have artificial neutral networks FAR larger than that and they run just fine. But they're so over-simplified that it's fair to call them something else entirely, not a simulation . You can use them to create similar behavior , but they're just following the basic concept of a brain, not how they actually work. Inspired by a real thing, not…
How do you verify precision of the simulation?
Re: Map of an Insect’s Brain
#124i intuitively think that there is something similar in kind between a fruit fly brain and a human brain regardless of the scale, and that cracking the smaller case will somehow lead to cracking the larger one. However, rather than hope, it leads me to a negative conclusion. That is, even at orders of magnitude smaller scales, and with full knowledge of how all the gross bits are connected, we still won't be able to u…
Explanations can exist at multiple levels. Reducing mind to neurons to atoms doesn't destroy/invalidate the emergent description at higher levels.
Just because we "know" the world is "made" of fields doesn't mean that the idea of objects is meaningless.
Re: Map of an Insect’s Brain
#125Is it simulated to the level where you could give it some visual stimulus and observe the actions it is trying to take? Could it be wired to a remote robotic insect and control it in real time? I've no idea how detailed these simulation projects and if we are months or decades away from doing what I mentioned
>Is it simulated to the level where you could give it some visual stimulus and observe the actions it is trying to take? No way. First, this mapping doesn't tell us how the synapses are regulated - if we could 'run' this the weights would stay fixed forever and that's not how a brain works. Second, there must be some neurons dedicated to chemical management, and they'd go haywire unless you found a way to deal with t…
Another approach is to try emulating different models of neurons/synapses/etc, and find models that act similarity to the real organism.
Investing the search space, to invent a name, can sometimes be very powerful.
Re: Map of an Insect’s Brain
#126Earlier quoted context omitted.
Yep, pretty much that thread. Massively simplified models exist, and yeah - we have artificial neutral networks FAR larger than that and they run just fine. But they're so over-simplified that it's fair to call them something else entirely, not a simulation . You can use them to create similar behavior , but they're just following the basic concept of a brain, not how they actually work. Inspired by a real thing, not…
How do you verify precision of the simulation?
In most cases the vague answer is "how closely can it recreate the end result". Because that's a useful measure.
For brains: we have no idea. Every brain is somewhat different, but we only have a couple complete physical layout maps so far. No "weights", no specific chemistry per cell, no knowledge of what may have changed before it could be frozen for imaging.
With a lot of work and a lot of extra physical and chemical simulation (a full body in quite a lot of detail), based on that map and what we know of the rest of its body, openworm achieves wormy wriggling.
That's honestly pretty good! And it implies that the connection structure is at least coarsely meaningful in an extremely simple mind, which is what many have suspected but have had no way to verify before. But we know next to nothing about how that individual worm's brain behaved compared to the simulation. The fly brain will be similar - we'll have a bigger and more complex brain to run, more complex behaviors to compare against other flies, etc. It'll provide more evidence in favor of or opposed to the importance of that structure, compared to other things that we don't have enough information on yet.
Basically it's still extremely early days, so it's sorta like asking Stonehenge astronomers whether or not our supernova-brightness-based measurements of the size of the universe are accurate. They can see supernovas too, but their answer has to be "uh. maybe? give us a few thousand years to research it". We need more data and better tools than currently exist.
Re: Map of an Insect’s Brain
#127Earlier quoted context omitted.
Thanks for the recommendation, tracking it down. And yes, modeling at the higher functional level can be very useful; knock out the Wernicke's center and speech goes, visual cortex, vision, etc... So, with a more detailed functional description of each level, we may wind up with a model with useful predictive value. Tho, that said, how does this approach create a truly robust abstraction from the lower level wetware?…
This is a little handwavy, but consider that, in the context of modelling a human brain: - If you model top-down (at the tissue/functional level like you suggest), you'll be recreating the "broadly correct" kind of computation, and you'll be recreating something that looks and feels like a really really bad, quirky and dumb human brain. But it'll have certain human-like qualities that are maybe even difficult to pin…
Thx - good points!
"multiple layers of emergent properties."
I think that is the key, right there! And we need to choose which layers are necessary, sufficient, and/or useful for the purpose.
Re: Map of an Insect’s Brain
#128Earlier quoted context omitted.
What is "awareness"? The only objective, measurable quantity is information complexity. (And yes, insects have it.)
Subjective experience of the world around us. The one thing I'm 100% sure I do have, and it would require very special pleading (or solipsism) to insist other humans are anything other than almost certain to share that trait. My suspicion is that there is some threshold of cerebral complexity required for it to occur, and is pretty unlikely to apply to all animals with central nervous systems. Whether insect brains a…
Information complexity is a physical quantity and we have many well-established methods of measuring it.