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Medical How does thinking create action potentials?

  1. Apr 11, 2010 #1
    Hello guys,

    I don't know much about brain and stuff I only know a bit about action potential. My question is I can understand how sensory nerves by a stimulus, but let's say I want to pick a pen. How does brain initiate the action potential for that? This might have been dicussed before but I'm not sure what to type in google to find the answer. Thanks :smile:
  2. jcsd
  3. Apr 11, 2010 #2
    You first recognize the need for an implement to write with... a decision must be made, which causes diffuse activity, but especially in the frontal lobe. You're still reacting to stimulus, at whatever remove.

    If you remove all external stimulus from a person, their mind will begin to create "phantoms" to fill the void. In the proper context, this is often an aspect of torture, although great care is taken because it is too easy to induce serious panic or even dissociation or dissociative fugue. That of course, makes information gleaned worthless.

    Now, if you enter a sensory deprivation 'tank', and you know you can leave it at any time.. some people find that same experience relaxing. Inevitably however, our brains provide stimulus in the absence of any external source. We are ALWAYS 'on'.
  4. Apr 12, 2010 #3


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    How can you be sure the decision to pick up the pen isn't a response to a stimulus?
  5. Apr 12, 2010 #4
    Of course, you can't be.

    http://hd.media.mit.edu/01.29.09_naturemag_secsig.pdf <-- Above quote.

    Really, there you have it.
  6. Apr 19, 2010 #5
    You decide to pick up a pen through various cascade pathways, you gather sensory information via afferent neurons, see pen, then your brain will send signals to your motor neurons, causing you to pick up the pen. Very very brief explanation, if you want more detail check out: http://wps.aw.com/bc_marieb_ehap_8/25/6527/1670985.cw/index.html [Broken]
    Last edited by a moderator: May 4, 2017
  7. Apr 22, 2010 #6
    What you are asking, I think, is how a purely volitional act originates in the brain; not as a direct response to some immediate or recent stimulus coming from the sensory input. This might be called "free will"; the idea that you can just decide to do something that is not effectively predetermined in some way. You'll find a lot of discussions about that, but no good answers. The fact is, no one knows. Neuroscientists however generally take the view that brain states are fully dependent on prior brain states (which take into account all sensory input) and there really is no such thing as 'free will'.
    Last edited: Apr 22, 2010
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