[Neuroscience] Re: Good book about left brain/right brain

r norman via neur-sci%40net.bio.net (by r_s_norman from _comcast.net)
Sun Oct 28 21:13:20 EST 2007


On Sun, 28 Oct 2007 22:01:42 +0000, konstantin kouzovnikov
<myukhome from hotmail.com> wrote:

>
>> receptors. But the subject matter of this discussion is left> brain/right brain.
> 
>True. I was wrong to interpret that there was a departure from the initial context.
> 
>>But at the> cellular level, try to show that gravity has any detectable effect. 
> 
>Was the "cellular level" a subject of the initial discussion?
>In any event, in your opinion, what would it take to register the influence of gravitational forces at cellular level? I am just curious.

Plants detect the direction of gravity with starch granules
(amyloplasts) inside the cells.  They are  more dense than the rest of
the cell and tend to fall to the bottom side of the cell.  The
membrane is specialized to detect these resting against the surface
probably through the influence of the actin cytoskeleton.
  Plant Gravitropism. Unraveling the Ups and Downs of a
    Complex Process
 Elison B. Blancaflor and Patrick H. Masson
 Plant Physiology 133:1677-1690 (2003)
 http://www.plantphysiol.org/cgi/content/full/133/4/1677
The vestibular system uses a similar method with calcarous statoliths,
except at the cellular level, not the intracellular.  

There are even magnetoreceptors in neurons that use magnetite crystals
embedded in the membrane to detect the magnetic field.  Yes, it is
possible to detect gravity and magnetic fields and electric fields.
But that is a far cry from saying that a theory of gravity or
electromagnetism has something to do with symmetry breaking in a
left-right side differentiation of brain function.  And, of course, a
developing animal is usually constantly shifting in position in a
gravitational or electromagnetic field so that external fields are not
likely to be able to  influence patterns of development in a specific
direction.


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