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Before starting to evaluate claims that this model will replicate any human behavior, I think it's important to consider the case of C. Elegans. It always has e

Before starting to evaluate claims that this model will replicate any human behavior, I think it's important to consider the case of C. Elegans. It always has exactly 302 neurons, and we know exactly how they connect to one another (we know its connectome), yet the furthest models have gotten with replicating its behavior is simplified, feedforward models of locomotion. In light of this, it is very hard to believe that we will be able to reproduce the behavior of 100 billion neurons which are constantly changing. This is not to say that Blue Brain is not an immensely useful tool to develop knowledge about the brain: it will be an excellent way to study what the implications of the vast amounts of data we have collected about the brain. However, to claim that the model will behave like a human brain seems like a stretch.

Devilboy 15y ago
The c elegans models are better that you think. Which nematode behavior is not able to be replicated by our models?
- dardila2 15y ago
  I'm not familiar with your models, but I'd be delighted to learn more. Could you post a link? EDIT: I was going off this quote from an article by well known computational neuroscientist Christof Koch: " Consider this sobering lesson: the roundworm Caenorhabditis elegans is a tiny creature whose brain has 302 nerve cells. Back in 1986, scientists used electron microscopy to painstakingly map its roughly 6000 chemical synapses and its complete wiring diagram. Yet more than two decades later, there is still no working model of how this minimal nervous system functions. Now scale that up to a human brain with its 100 billion or so neurons and a couple hundred trillion synapses. Tracing all those synapses one by one is close to impossible, and it is not even clear whether it would be particularly useful, because the brain is astoundingly plastic, and the connection strengths of synapses are in constant flux. Simulating such a gigantic neural network model in the hope of seeing consciousness emerge, with millions of parameters whose values are only vaguely known, will not happen in the foreseeable future."
  - Devilboy 15y ago
    I'm not an expert so I could be wrong but over the last 10 years I've seen many papers on various details and behaviors of the C. Elegans nervous system. I agree we have a lot still to learn from it but we certainly seem to know enough to simulate it accurately and get the same kinds of behaviors that we see in the living worm. We've even been able to simulate much larger and more complex systems like the fruitfly eye and direction-tracking system. I really believe that all we need to have is the connectome and the rules it uses to organize and change itself. We don't need to know EVERYTHING about it.
    - dardila2 15y ago
      The sense I get of it is that they can custom build neural network models of various sub-circuits to produce certain behaviors, but no one has been able to take the connectome and build a 302 neuron model that replicates any behavior. Would you agree? I've searched for quite a long time for something like this and talked to a couple faculty members to no avail, so if you could turn up anything I would be very happy to read about it. I agree with you on your last point: we can replicate behavior without going to a very low level of simulation. However, the case of C. elegans seems like very strong evidence that the connectome and current knowledge of update rules is not enough to create a model of an organism that replicates behavior.
      - Devilboy 15y ago
        I think you are correct, I can't seem to find anyone that's actually simulated the complete nervous system and reproduce any behaviors.

Devilboy 15y ago

The c elegans models are better that you think. Which nematode behavior is not able to be replicated by our models?

dardila2 15y ago
I'm not familiar with your models, but I'd be delighted to learn more. Could you post a link? EDIT: I was going off this quote from an article by well known computational neuroscientist Christof Koch: " Consider this sobering lesson: the roundworm Caenorhabditis elegans is a tiny creature whose brain has 302 nerve cells. Back in 1986, scientists used electron microscopy to painstakingly map its roughly 6000 chemical synapses and its complete wiring diagram. Yet more than two decades later, there is still no working model of how this minimal nervous system functions. Now scale that up to a human brain with its 100 billion or so neurons and a couple hundred trillion synapses. Tracing all those synapses one by one is close to impossible, and it is not even clear whether it would be particularly useful, because the brain is astoundingly plastic, and the connection strengths of synapses are in constant flux. Simulating such a gigantic neural network model in the hope of seeing consciousness emerge, with millions of parameters whose values are only vaguely known, will not happen in the foreseeable future."
- Devilboy 15y ago
  I'm not an expert so I could be wrong but over the last 10 years I've seen many papers on various details and behaviors of the C. Elegans nervous system. I agree we have a lot still to learn from it but we certainly seem to know enough to simulate it accurately and get the same kinds of behaviors that we see in the living worm. We've even been able to simulate much larger and more complex systems like the fruitfly eye and direction-tracking system. I really believe that all we need to have is the connectome and the rules it uses to organize and change itself. We don't need to know EVERYTHING about it.
  - dardila2 15y ago
    The sense I get of it is that they can custom build neural network models of various sub-circuits to produce certain behaviors, but no one has been able to take the connectome and build a 302 neuron model that replicates any behavior. Would you agree? I've searched for quite a long time for something like this and talked to a couple faculty members to no avail, so if you could turn up anything I would be very happy to read about it. I agree with you on your last point: we can replicate behavior without going to a very low level of simulation. However, the case of C. elegans seems like very strong evidence that the connectome and current knowledge of update rules is not enough to create a model of an organism that replicates behavior.
    - Devilboy 15y ago
      I think you are correct, I can't seem to find anyone that's actually simulated the complete nervous system and reproduce any behaviors.