Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The Brain

  1. Oct 3, 2003 #1
    Is it possible for us to make a functional model of the human brain?
    I'm not interested in the phylosophical implications, but more in the resources, techonolgies we can use (that's why I posted here.... )
  2. jcsd
  3. Oct 3, 2003 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Why not start small?

    How about a honeybee? Or a simple worm?

    If those could be modelled, wouldn't the human brain just be a matter of scaling up?
  4. Oct 3, 2003 #3
    hi Nereid :smile:

    I don't think insects have a central nervous system (I could be wrong though...).
    What animal has the simplest brain; is there a biologist here that can answer that?
    just found this link here: http://www.artificialbrains.com/ for anybody interested
  5. Oct 3, 2003 #4


    User Avatar
    Science Advisor

    Not quite.

    Mammalian brains are different from reptiles and birds, which are different from fish which are different from invertabrates.

    I think a human brain can be modelled. It is a physical entity after all. However, not all of its functionality is understood, and what is understood is tremendously complex.

  6. Oct 3, 2003 #5


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    What are the key differences?

    What is the simplest mammal, from the brain perspective?
  7. Oct 3, 2003 #6


    User Avatar
    Science Advisor

    I'm no expert, and would screw up the details I'm sure. Try this link:


    I'm not qualified to judge the info on the site. Hopefully, one of our biology experts will critique the ideas presented at this site, and maybe come up with a better one if they find it lacking.

  8. Oct 6, 2003 #7
    What if you wrote a physics engine in a computer language and programmed in every atom of a human brain? :)
  9. Oct 7, 2003 #8
    well I was hoping of something that could be done in my lifetime...
  10. Oct 7, 2003 #9
    Unless you're extremely old, it could! All we need is a very fast computer with a ton of memory, and we can program a program that sets up every atom, after detecting it in a machine with a dead human brain (or some such thing) in it.

    Something like that, anyway. It's not as impossible as it sounds...
  11. Oct 7, 2003 #10
    (pay no attention to the man behind the curtain!)


    It is most definitely not possible. There is, at this time, a worldwide effort underway to simply map the human brain. In other words they still haven't sorted out what functions different parts of the brain perform.

    If you take vision, for example, they know this is primarily processed in the occipital lobes, but important aspects of vision, such as the perception of up and down motion, are processed in the parietal lobes. Other aspects are processed in the temporo-parietal area. What is one phenomenon to us: vision, is actually the perception of many different aspects of vision fused into the one we're conscious of.

    No one even thinks to consider we need a system to process the perception of up and down motion till it gets damaged in someone.
    We don't know how many things the brain does that we haven't even realized needed doing.

    The functions performed by the brain are, therefore, probably still not all discovered, and it is taking imput from neurologists all over the world, to simply create this comprehensive map.

    That being the case it is clear they don't know remotely enough to create a functioning model of the circuitry.

    If you'll settle for a good plastic brain model go here:

    Brain Mart's Brain Models

    Last edited: Oct 8, 2003
  12. Oct 7, 2003 #11


    User Avatar

    Ah yes, I raised this in the chat, didn't I?

    I think the whole issue is that of acceptable approximation. It is not required that we model every atom etc, but rather just understand what each individual cell or group of cells does and translate this into an entire system. If there are parts of the brain we don't know about... then modelling them would be outside the scope of our model's criterias.

    In using GR as a model of the universe, we do not claim that GR covers all things we do not even know. Rather, we judge the acceptability of the model on what we already know...
  13. Oct 8, 2003 #12
    IMO the great challenge is to make a system that can learn. No system made by man can do that yet. It may not be obvious but computers work on algorithms. Every algorithm in use today was made from scratch by men. There isn't a algorithm that was made by a computer. I think that if we want to make a model of the brain sooner or later we must design a system that can learn...

    the human genome project lasted 13 years and al they did was mainly:
    - identify all the approximately 30,000 genes in human DNA,
    - determine the sequences of the 3 billion chemical base pairs that make up human DNA.
    Tenths of institutes have joined resources to make this happen. (http://www.genome.gov/ )
    And you want ot map every atom in the brain and believe it can be done in a lifetime? You're too optimistical :smile:

    that's a start as good as any other...
  14. Oct 8, 2003 #13


    User Avatar
    Science Advisor

    Modelling the brain in isolation is not really a model of the brain as it works in humans. There is significant bio-feedback from chemicals produced in other parts of the body. For example, eyes detect tiger, tiger is referenced in brain, brain tells adrenal glands to produce adrenaline, adrenaline affects neurotransmission, brain works differently.

  15. Oct 8, 2003 #14
    Guybrush wants a functioning model, a very tall order, and one which means a physical apparatus that does something, as opposed to a conceptual model, such as "Bohr's model of the atom".

    If we were to make a functioning apparatus based on what we do know about the brain, leaving out the parts we don't know about, it really wouldn't be a model of a human brain at all. With luck it might amount to a functioning model of a very damaged human brain.

    Njorl's post points out the that the functioning of the brain as we know it extends out and into the body. I hadn't thought of that. Guy's model would actually require
    a functioning model of the body to be built as well, to support it.
  16. Oct 9, 2003 #15
    u can only create a probabilistic model using AI algorithms like genetic algo and neural networks, which themselves are derived from biological principles on which our brain and nervous system works. so, the fuzziness in our final model will definitely limit the efficiency, and we will end up with a brain that does not, or rather, can not ,THINK ....
  17. Oct 9, 2003 #16
    model atoms of brain?

    Modelling the atoms may be too ambitious, but modelling the individual functions could be also. The power contained in the brain comes from the fact that all of these functions interact synergistically, so that the whole is more than the sum of the parts, and we may never be able to determine all of the unseen interactions that take place when several functions combine to produce a thought. Rather, let's consider the middle road. Just model the connections between neurons, and the conditions that cause each synapse to fire (kind of like the game of life). I picture an AI containing groups of synapses of various characteristics - in this group, two inputs (on average) cause a firing while in that group it may be that 5 inputs are required. As stated, chemical processes can change the characteristics of the neurons, but such chemical processes would be fairly easy to model as a possible output of certain groups having high activity at the same time, and this causing a global change throughout the AI, with various affects to each group. In summary, I believe the synergistic characteristics of the brain come mainly from the circular feedback of various neuron groups each having DIFFERENT firing rules on average. Also important would be if one group, for example, comes between a pair of groups in the normal communication scheme, i.e. the corpus colosum connects the hemispheres, but modifies the info going between them.
    Just some random thoughts on the subject.
    Last edited: Oct 9, 2003
  18. Oct 10, 2003 #17
  19. Oct 13, 2003 #18

    I'm picturing the brain as being multiple neural networks, having feedback between many pairs of such networks. In both the brain and in all other complex biological, chemical, and physical systems that exhibit synergistic effects and emergent phenomena, feedback is the key. Without feedback, things go in a linear fashion. With feedback, surprises can result! Picture a corporation running with information and direction going only from the top down - disaster! The management will be out of touch with what is going on below them, and even in parallel branches of the corporation. Those who implement policies will have no recourse when conditions change and the directions they were given no longer fit the situation they now find themselves in. Parallel branches may act against the goals of each other - a schizophrenic corporation. Now add upward and sideways feedback and voila, we now have an intelligently run corporation. It's the same way with the brain. In simplistic terms, at the very least we have feedback between memories, reasoning, input, planning, output, emotions (intuitions, hunches), feelings, imaginings, etc. How many different facets of thought are there - I'd like people to supply their own answers to this here, if they think it would help the thread. Now, how many of these facets are stand-alones, don't give or receive feedback from other facets during normal thinking?
    Last edited: Oct 13, 2003
  20. Oct 13, 2003 #19

    From what I understand of the brain you are on the right track.
    All the different parts of the brain are constantly in communication with other parts, back and forth.

    I would only suggest that for the "multiple neural networks" of the first sentence of your last post you substitute "multitudinous neural networks." Earlier today I was looking through a book on the brain and became aware of yet more things the brain does that I hadn't ever considered needing doing.

    You have also to take into account the all important, constant stream of new information coming in through the sences. The more I consider the brain/body/environment interaction the less I think it is possible to construct even the crudest of functioning models.
  21. Oct 21, 2003 #20


    User Avatar
    Homework Helper

    What do you mean by "learn?" In the simplest, zeroth order sense, is not any response to stimulus learned?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: The Brain