[HN Gopher] The Power of Small Brain Networks
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       The Power of Small Brain Networks
        
       Author : dnetesn
       Score  : 57 points
       Date   : 2024-11-18 08:25 UTC (7 days ago)
        
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 (TXT) w3m dump (nautil.us)
        
       | bloodyplonker22 wrote:
       | This power is quite obvious when you consider that a lot of
       | answers that you get from AI these days is from Reddit.
        
       | ilaksh wrote:
       | One thing to mention is that as far as I know, biological neurons
       | are much more complex than artificial ones. They spike and have a
       | lot more internal states (I think).
       | 
       | I wonder if we might see more neuromorphic AI hardware (at
       | competitive scale) soon in order to get away from the extreme
       | energy requirements by (hopefully) packing more capability into
       | fewer artificial neurons and/or a more efficient implementation
       | of the neurons.
       | 
       | Every time I see another headline about the plans for giant AI
       | datacenters I expect the next one to be about memristors or some
       | new paradigm with a huge investment coming out of a lab and into
       | a competitive chip. I think that every dollar that goes into a
       | giant AI datacenter should be matched with trying to make new
       | hardware paradigms for AI competitive.
        
         | sdenton4 wrote:
         | I doubt it... The last, oh, ten years has been accompanied by a
         | graveyard of dead neurotrophic ai startups. Brain neurons are
         | what they are because they are working under a particular set
         | of capabilities and constraints, very different from what we
         | can do with silicon.
         | 
         | It's also worth asking whether the data center is really all
         | /that/ inefficient: The human time and effort required to
         | produce (say) one text-to-image prompt completion is enormous
         | compared to a GPU: the brain uses less power per time unit, but
         | seems to require a hell of a lot more time.
        
         | kuukyo wrote:
         | I also think neuromorphic computing is the future for energy
         | efficient AI. But sadly development is getting a bit sidelined
         | by other popular AI research areas. It doesn't help that it's
         | much easier to train ANNs than spiking neural networks (SNNs).
         | :/
        
           | bob1029 wrote:
           | I think neuromorphic might even be a distraction right now.
           | 
           | The hyperparameters for a SNN that performs a specific task
           | are extremely elusive. If you don't even know what kind of
           | neuron model or fan out ratio _might_ work, how the hell can
           | you start burning these as constants into some hardware
           | contraption?
        
         | Roxxik wrote:
         | I'm not sure that the analogy stretches so far.
         | 
         | What even is an artificial neuron in an Artificial Neural
         | Network executed on "normal" (non-neuromorphic) hardware? It is
         | a set of weights and an activation function.
         | 
         | And you evaluate all neurons of a layer at the same time by
         | multiplying their weights in a matrix by the incoming
         | activations in a vector. Then you apply the activation function
         | to get the outgoing activations.
         | 
         | Viewing this from a hardware perspective, there are no
         | individual neurons, just matrix multiplications followed by
         | activation functions.
         | 
         | I'm going out of my area of expertise here, I just started
         | studying bioinformatics, but neurological neurons can't simply
         | hold an activation because they communicate by depolarising
         | their membrane. So they have to be spiking by their very nature
         | of being a cell.
         | 
         | This depolarization costs a lot of energy, so they are
         | incentived to do more with less activations.
         | 
         | Computer hardware doesn't have a membrane and thus can hold
         | activations, it doesn't need spiking and these activations cost
         | very little on their own.
         | 
         | So I'm not sure what we stand to gain from more complicated
         | artificial neurons.
         | 
         | On the other hand, artificial neutral networks do need a lot of
         | memory bandwidth to load in these weights. So an approach that
         | better integrates storage and execution might help. If that is
         | memristor tech or something else.
        
           | ilaksh wrote:
           | Cerebras uses SRAM integrated into a giant chip I think. It
           | is extremely fast inference -- they say 70 X faster than GPU
           | clouds, over 2000 tokens per second output of a 70b model.
           | But still uses a ton of energy as far as I know. And the
           | chips are, I assume, expensive to produce.
           | 
           | Memristors might work, to get the next 10 X or 100 X in
           | efficiency from where Cerebras is.
           | 
           | As far as more complex neurons, I was thinking that if each
           | unit was on a similar order of magnitude in size but somehow
           | could do more work, then that could be more efficient.
        
         | erikerikson wrote:
         | > biological neurons are much more complex than artificial
         | ones. They spike and have a lot more internal states (I think)
         | 
         | This is correct. Notably the famous Minsky XOR result is valid
         | only due to oversimplification in the perceptron model. By
         | adding a notion of location and modulating learning using it,
         | Hopfield networks learn XOR just fine.
        
       | lukah wrote:
       | How do they track the brain activity of a fruit fly? That seems
       | incredible to me
        
       | ValentinA23 wrote:
       | >The scientists monitored the brains of fruit flies as they
       | walked on tiny rotating foam balls in the dark, and recorded the
       | activity of a network of cells responsible for keeping track of
       | head direction.
       | 
       | Meanwhile I chimp out when I have to plug 4 wires in a relay
       | module.
        
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