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Thread: How does body movement work?

  1. #1 How does body movement work? 
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    For eg. if I want to lift my finger, I think about it consciously or sub-consciously but my brain instantaneously decides which muscles to contract and which to expand in order to bring about the desired movement. The brain sends the signals via the correct nerves to the correct muscles.
    How does it do that?? Is it the cortical honunculus? How does it work?
    I've read about "brain sending electro-chemical signals through nerves to the brain" but is there anything we know about how does the brain decide the correct pathway (nerve, I mean) to the correct muscle. Please keep in mind that I consider brain sitting at least a meter away from the muscle in the finger. I hope you are getting what I am trying to say.[/b]


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  3. #2  
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    Correction- "Brain sending electro-chemical signals through nerves to muscles"


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  4. #3  
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    The whole question is enormously complex. The brain takes in sensory signals, such as vision, and processes them. The processing can be conscious, unconscious, or pure reflex. A decision is reached by that processing on some action in response, and the signal is sent down the appropriate nerves. Some of the sensory input seems to be internal - basically just thoughts, conscious or otherwise.

    There is no simple answer. The whole thing is poorly understood even by neuroscientists.
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  5. #4  
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    Ok. Does the orientation of muscle tissue count in movement i.e. if the shape of a muscle tissue is deformed, does it mean that the movement gets restricted? (I'm guessing it does.)


    And like for a particular stimulus, a particular area of the brain lights up (as seen in the brain scans), does it mean that brain has a precise map down to the cellular level?


    And similarly, a map of nerves in the body?
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  6. #5  
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    Proprioception is one of the 22 plus senses we all possess. Proprioceptor cells in muscle tissue measure the degree of muscular contraction, and pass that data through nerve cells back to the brain. The brain takes that into account in the signals sent to move muscles.
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  7. #6  
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    Do scientists have a clue as to how proprioception works?

    Each proprioceptor cell has to have the information of its location in the body. Or is the map located in the brain?


    Is it even a "map"? The question becomes even more complex if we consider different body plans that animal kingdom has. With each step in evolution, this sense has to fine-tune according to the body plan.

    Imagine if we were to replicate this in a robot, each proprioceptor will have a prior stored information about it's location and a pathway to send this information to a processor. That would mean enormous information.

    Is there another conceivable way in which it might work?
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    Yes, there is a 'map' in the brain. It has even been elucidated by using probes to stimulate parts of the brain. So we know which part of the brain represents the left ear etc. The 'map' is distorted. So, for example, the part of the brain representing the thumb is massively larger than the part representing the big toe. This is due to the larger number of nerve cells running from the brain to the thumb. More information comes from the thumb, and more signals to the thumb muscles than to and from the big toe.

    Books on neuropsychology often carry a picture of this mental map.

    In an animal brain, the 'map' would be distorted in a differnt way representing the relative importance of different parts of the animal's body. For example, I predict an elephant has a mental map with the trunk enormously over-large.

    Proprioceptors are linked to the brain by a nerve pathway. The brain 'knows' each proprioceptor by the unique pathway.
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  9. #8  
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    Thanks! That was really helpful.


    Here's an interesting article about cyborg insects-

    http://www.newscientist.com/article/...-distance.html

    and a video-

    http://www.youtube.com/watch?v=dSCLB...eature=channel

    It made things a little more clear to me.
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  10. #9  
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    hallo allemaal, net nieuw in dit forum .. leuk je te ontmoeten .. koele plaatsen =)
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  11. #10  
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    leuk je te ontmoeten!
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  12. #11  
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    This doesn't really relate to the topic in question, it's just a correction, but there are no muscles in your fingers. Tendons run down the length of your fingers and the muscles in your forearms pull them.

    The thumb does have muscles though.
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  13. #12  
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    Ok thanks!
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