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Ununiform blood flow to the hemispheres of the brain

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Ununiform blood flow to the hemispheres of the brain

Postby ragav.payne » Thu Jan 10, 2008 6:02 pm

Hello,

Perhaps this is a naiive question...naiive because of the lack of my knowledge of the blood circulation system of the brain.

Anyway, I was wondering if increasing the blood flow to one hemisphere would improve its activity or dominance (at least temporarily).

I came up with this question because, sometimes, when I'm sitting somewhere or listening to a lecture or something of that sort, I become conscious of my posture suddenly and realize that I'm tilting my head to one side. My head is usually closer to one shoulder...and this realization occurs after I've spent a lot of time in that posture. So, I spend a significant amount of time in that tilted posture. I don't really know if this can somehow affect the normal functioning of the brain, but I just was wondering if the blood circulation system could be designed so as to let gravity affect the distribution of the blood flow.

If it does affect hemisphere dominance, then the implication would be colossal! Just tilting your head would make you the person you want to be. If you'd like to think more objectively, just tilt your head to your left!! I have to say, it does sound like a crackpot theory.

So, what do you think?

Regards.
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Postby MrMistery » Thu Jan 10, 2008 6:24 pm

I'm sorry to say, but yes it does. Hemisphere dominance has nothing to do with blood circulation. Actually i don't think that old hypothesis that the left is for analysis and right for synthesis still stands. It's a sort of an urban mith, like us using 16% of our brain(which is of course false).
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Re:

Postby MichaelXY » Fri Jan 11, 2008 4:10 am

MrMistery wrote:I'm sorry to say, but yes it does. Hemisphere dominance has nothing to do with blood circulation. Actually i don't think that old hypothesis that the left is for analysis and right for synthesis still stands. It's a sort of an urban mith, like us using 16% of our brain(which is of course false).
Sorry


I would not call this hypothesis old, as Roger Wolcott Sperry was a Nobel laureate in 1981 for his work in split brain research. I will concede that much of this topic is in debate, but I would say this is not as simple as a urban myth.
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Postby MrMistery » Fri Jan 11, 2008 12:55 pm

of course the two hemispheres of the brain have different functions(like the Broca region in the dominant hemisphere). but i doubt anyone can provide some solid scientific proof that one hemisphere or the other helps you do math. At least not in the present; who knows what the future holds?
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Postby ragav.payne » Mon Jan 14, 2008 6:36 pm

So, is it true that increasing the blood flow to the entire brain helps in increasing its activty? (Actually, this seems to stem up as a corollary of the fact that the more active an organ, the more oxygen it demands)

If it is, then why shouldn't increased bloodflow to one part of the brain increase its function?
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Postby MichaelXY » Mon Jan 14, 2008 9:04 pm

I think the body has an autoregulation mechanism for blood flow, such as dialation of vessels. This is needed to deliver constant blood flow. So I really do not see tilting your head would really have any affect.
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Postby MrMistery » Tue Jan 15, 2008 8:14 am

Maybe an increase in blood flow would do that. But don't forget that a neuron dies in a few seconds without oxygen. If you ask me, oxygen to the brain(if you don't have problems) is always at an optimum
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Postby genovese » Tue Jan 15, 2008 1:58 pm

Look up this site for the circulation to the brain http://www.bartelby.com/107
and you will see that you cannot increase blood flow to any part of the brain by mechanical means such as head tilting because of the joining up of the 4 major vessels (two internal carotid arteries and two vertebral arteries) at the base of the brain to form the Circle of Willis.

Even with diseased and clogged up Carotid arteries people can have no symptoms whatsoever with even 60% and more blockage of a carotid artery (showing the efficiency of the Circle of Willis). However, although you cannot increase the blood flow to the brain, you can reduce it by mechanical means once the arteries become blocked. Many elderly folk are aware of giddiness if they extend their necks, temporarily cutting off blood flow to the cerebellum with inadequate supply from the other vessels through the Circle of Willis. Major cerebral vascular accidents have occured (though rare) through manipulating the cervical spine.

So we cannot increase brain blood flow by head tilting etc but if vessels are damaged you could significantly decrease brain blood flow by mechanical means.
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