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  1. #1
    la vache fantôme phantomcow2's Avatar
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    Can somebody explain this, about the human brain?

    I don't know if anybody here has done significant studies of the human brain, and is overall knowledgeable and understanding of its operations. If you have, can you answer a few questions?

    It is my understanding the the brain has many parts to it, each with its own task. Some parts work together in instances though. I understand there are some sort of electrical impulses also, which is how the different components of hte brain communicate. Am I correct?

    What are these impulses? Pulses of minute amounts of DC voltage?

    If they are....
    Does the ohmic resistance of brain tissue have any correlation with intelligence?

  2. #2
    riding once again jschen's Avatar
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    The nervous system works via tiny electrical pulses generated by controlled gating of sodium and potassiumm channels. Only the time points of the pulses matter. Pulses in the same nerve are always nominally the same strength and duration. Therefore, ohmic resistance and intelligence presumably have no correlation.
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  3. #3
    Prefers Cicero cooker's Avatar
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    The brain is comprised of neurons, or nerve cells that have long connecting branches call axons. The body of the cell may be in one part of the brain and the axon may communicate with a cell right next two it or several inches or even several feet away in the brain or spinal cord. The axons carry electrical impulses but at the termination they release a chemical neurotransmitter that crosses a tiny gap (the synapse) to the next cell and activates a highly specific receptor. There are many different neurotransmitters and receptors. Some activate the part of the brain they reach, others inhibit, others modulate the effects of other neurotransmitters. The brain also has receptors for circulating hormones and receives incoming information from the body via the spine and sparately via the cranial nerves. The axons also have "pre-synaptic" receptors that monitor how much information they are sending out and shut themselves off. There's a lot going on. The brain does seem to be organized into various clusters of nerve cell bodies, and various tracts of axons, but the pathways are far too complex and numerous to map in any kind of fine detail. We have crude ideas about which parts of the brain do what.

    One interesting and counterintuitive fact is that in childhood you may actually have too many neurons and in fact part of the maturation of the brain involves "pruning" or selective deletion of many of your neurons. At the same time new branches and connections are being formed, and supportive cells are surrounding the axons with layers of insulation called myelin, presumably to refine the communication among clusters of cells.

    If your brain is damaged and loses neurons it usually can't replace them but the remaining ones can grow new branches and receptors, so presumably that accounts for some recovery. The hippocampus and olfactory bulb are two areas that seemingly can grow more neurons, but the significance of that is unknown.

    Enough for now.
    Last edited by cooker; 08-03-06 at 06:20 PM.

  4. #4
    Prefers Cicero cooker's Avatar
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    Just to finish addressing the question, the electrical message travelling down an axon is dependent on the chemical gating JSChen mentioned, but intelligence is probaby related to the overall architecture of the brain, such as how many pathways there are, and what connects to what. As well, intelligence may be partly hereditary, but it also seems to be influenced a lot by early childhood intellectual stimulation, presumably through it's influence on pruning and sprouting of neurons.

  5. #5
    la vache fantôme phantomcow2's Avatar
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    Thanks .
    Can you tell me a bit about these electrical impulses? Are these short bursts of minute DC voltage, carrying minute amounts of current?

    I was just wondering if hypothetically,
    you implant a high value ohmic resistor between components of the brain, significantly decreasing the speed at which electrical impulses can reach their targets. Would that mean it would take longer times for you to process thoughts?
    On the contrary, what if you were to implant a known excellent conductor such as silver metal, couldn't this mean that the brain essentially has to work 'less hard' to process information? Perhaps giving you the ability to think faster.

  6. #6
    la vache fantôme phantomcow2's Avatar
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    Oh, and does the brain fluctuate these electrical impulses? Perhaps we as a species have had encounters with pulse width modulation before the use of it in motor speed control....

  7. #7
    Non Tribuo Anus Rodentum and off to the next adventure (RIP) Stacey's Avatar
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    Dood, kin eye ave som o wot yer smokin?

  8. #8
    On my TARDIScycle! KingTermite's Avatar
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    I'm going by memory here, so bear with me, my facts may not be 100% correct, but pretty damn close. This is a topic we covered in my graduate level Neural Networks class. As you know the brain is basically an organic neural network.


    Yes, the impulses are DC and very small (maybe not as small as you think though).

    The brain uses axons and dendrites as a connection network. The chemical reaction at the end which induces the flow of electricity (cross the synapse) is different in each one. The chemical reaction determines the speed and strength of the synapse firing.

    A neural network has many "cells" each which is connected to one or more other cells. These connections basically have different strengths (weights). A cell has many connections coming in to it and its output is basically a simple mathematical calculation of connections that came in to it. Essentially it does this all the way through the network until its output somewhere is given a value.

    A brain is an organic version of this, but even more complex. It doesn't really have one network with one output, but many networks (the various "regions" of the brain) and they are all interconnected and probably all have their own seperate outputs (or many). So its like many neural networks all inter-tied together. Far more complex than any computer neural network we've ever created.

    So your question about using a resistor or conductor to speed up processing is false. What it would likely do tamper with the neural network so that the wrong signal comes through because you've tamped with its voltage (weight).

    If you want more detailed info on this, try adding "neural network brain" to your google terms.
    Quote Originally Posted by coffeecake View Post
    - it's pretty well established that Hitler was an *******.

  9. #9
    la vache fantôme phantomcow2's Avatar
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    I see, so the brain is at an equilibrium now? Tampering would the voltage either way you only cause problems.
    Thanks, thats all I wanted to know.

  10. #10
    Immoderator KrisPistofferson's Avatar
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    Quote Originally Posted by The Anti-MERTON

    If they are....
    Does the ohmic resistance of brain tissue have any correlation with intelligence?
    That I don't know.
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    Prefers Cicero cooker's Avatar
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    The axon is a tube which contains and is surrounded by electrolyte solution. There is a charge differential between the inside and outside, due to active pumping of certain ions from one side to the other. The electrical signal occurs when a section of the tube wall becomes activated, opening the ion channels and causing an equalizing flow of electricity and ions through the axon wall. This "depolarization" activates the next section of tube, so a wave of electrochemical activity flows down the tube, something like a row of falling dominos, or the crowd doing "the wave" in a stadium. Once the signal has passed, the pumps are then reactivated and the charge differential is restored, until the next signal comes along.

  12. #12
    la vache fantôme phantomcow2's Avatar
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    One more thing,
    For two given parts of the brain. Do we know yet if the DC voltage is consistent? DOes it ever fluctuate? ANd if it does, wouldn't this have adverse effects?

  13. #13
    la vache fantôme phantomcow2's Avatar
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    Further more,
    If in fact the voltage between various parts of the brain should be consistent, do variations cause any known problems?

  14. #14
    riding once again jschen's Avatar
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    Quote Originally Posted by phantomcow2
    I see, so the brain is at an equilibrium now?
    No way! Chemically speaking, life is about maintaining non-equilibrium steady state. A body at equilibrium is a dead body.
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  15. #15
    la vache fantôme phantomcow2's Avatar
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    Sorry,
    What I meant was that I was wanting to know if hte voltages produced by the brain were consistent, for a given region.

  16. #16
    On my TARDIScycle! KingTermite's Avatar
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    Quote Originally Posted by phantomcow2
    I see, so the brain is at an equilibrium now? Tampering would the voltage either way you only cause problems.
    Thanks, thats all I wanted to know.
    No.

    Not at equilibrium. What I mean is you would tamper with the weights doing that, so it would "compute wrong answers". That is, it would be sending the wrong signals because you tampered with the weights in the neural network.
    Quote Originally Posted by coffeecake View Post
    - it's pretty well established that Hitler was an *******.

  17. #17
    la vache fantôme phantomcow2's Avatar
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    Thanks all,
    as usual, I am not surprised to find answers to my questions at bikeforums

  18. #18
    Prefers Cicero cooker's Avatar
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    Quote Originally Posted by KingTermite
    As you know the brain is basically an organic neural network.
    Really?

  19. #19
    On my TARDIScycle! KingTermite's Avatar
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    Quote Originally Posted by cooker
    Really?
    Undoubtedly.

    Do a google...it's very well documented.

    I took a graduate level neural networks class a few years ago when I was working on my Masters and the whole first few weeks of the class were actually spent learning how the brain's neural network worked.
    Quote Originally Posted by coffeecake View Post
    - it's pretty well established that Hitler was an *******.

  20. #20
    Prefers Cicero cooker's Avatar
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    Quote Originally Posted by KingTermite
    Undoubtedly.

    Do a google...it's very well documented.

    I took a graduate level neural networks class a few years ago when I was working on my Masters and the whole first few weeks of the class were actually spent learning how the brain's neural network worked.
    And where did neural networks come from, and why are they called that?

  21. #21
    Retro-nerd georgiaboy's Avatar
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    Oh, Doctor Phantomcow, this is Igor, I have the brain you requested!!! Oh! Sorry Sir! you told me never to contact you in BFs. I will send you an email. We will complete the project this time Doctor. We will CREATE LIIIIIIIIIIIFFFFFeeee!!!!!
    Last edited by georgiaboy; 08-04-06 at 09:10 AM.
    Would you like a dream with that?

  22. #22
    On my TARDIScycle! KingTermite's Avatar
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    Quote Originally Posted by cooker
    And where did neural networks come from, and why are they called that?
    I believe they came from humans trying to mimick the brain because it seemed to work so damn well. LOL

    They call them that because they are a network of neurons I guess. A neuron is a generic term for each unit (axon + dendrite), if I recall correctly.

    Wikipedia:
    http://en.wikipedia.org/wiki/Neural_network

    After reading wikipedia's spin, I remember it is important to specificay in computers we call them "artificial neural network" I guess to distinguish it froma "real" one (like the brain). AFFs are also closely related with Artificial Intelligence.
    Quote Originally Posted by coffeecake View Post
    - it's pretty well established that Hitler was an *******.

  23. #23
    Non Tribuo Anus Rodentum and off to the next adventure (RIP) Stacey's Avatar
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    Quote Originally Posted by phantomcow2
    Further more,
    If in fact the voltage between various parts of the brain should be consistent, do variations cause any known problems?

    Yes, ever heard of electro shock therapy and semi vegatative state?

  24. #24
    Señor Member USAZorro's Avatar
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    There are a number of problems that people can experience due to either the overabundance of, or a deficiency of neurotransmitters. I don't know specifically how this relates to the overall voltages involved. I've been out of the literature ever since college so this may be out-of-date, but I do remember learning that there is a certain "background" rate of neural firings that occurrs - sort of a "white noise" if you will. In order for some actual action to be performed, some threshold of reinforced neural firings needs to be achieved along the pathway. I don't know if the cumulative effect of the reinforcement would alter the voltage involved or not. It seems to me that if one considers cumulative electrical activity in the brain, there are two extremes. Almost no activity, and you have a coma. More activity than can be handled, and you have convulsions.

    Don't know if this helps phantomcow.
    The search for inner peace continues...

  25. #25
    Footballus vita est iamlucky13's Avatar
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    Regarding putting resistors in the path, the dendrites branch, presumably to give a diffuse pathway and make it difficult for any particular obstacle to disrupt the flow of electrons.

    If I remember correctly, the voltage is consistently around 70 mV (if I remember right) and it's the voltage rather than the current that matters. Basically nothing happens in a neuron until the electrical potential reaches that 70 mV level, at which point something happens with the sodium and potassium balance (jschen probably knows more about this) that allows the voltage to dissipate and I think triggering the next neuron in the chain.
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