[EMAIL PROTECTED] wrote:
In a message dated 3/6/2006 6:05:52 PM Eastern Standard Time,
[EMAIL PROTECTED] writes:
go ahead and ask you now. What do you think about minicolumns?
I read something about them that cited
http://cercor.oxfordjournals.org/cgi/reprint/bhj134?ijkey=WZG8KUzGqERqQub&;
keytype=ref http://tinyurl.com/pdxv3 if that link broke
and in the comments of the thing I read someone indicated that it's
a controversial theory. I figure you know a lot more about brain
structure than I do, so you'd be a reasonable person to ask.
wow! I am impresed that you got to such a hard core science paper.
The notion that the cortex develops in columns is not as far as I
know controversial. The germinal matrix is the embryologic structure
where neuronal precursors are produced. These migrate to the surface
of the brain along a scapholding made up of other cells called radial
astrocytes. The two major cell types in the brain are neurons (the
nerve cells that carry out the computational functions (that is, the
important stuff) and glial cells that provide other functions to the
brain in terms of maintaining the necessary chemical environment,
forming the linings of the brain, providing nurishment to the white
matter, acting as the immune cells of the brain etc. Astrocytes are
the most common of these glial cells. In the developing brain
beginning in the second trimester. These glial cells migrate away
from the central cavities of the brain. The neurons then grow out
along the radial glial cells to reach their appropriate position. If
this process is disrupted or disorganized abnormalities of cortical
formation occur. When this process is focal clefts are produced in
the brain extending from the central cavities (the ventricles) to the
surface of the brain. These clefts are called schizencephaly. If the
radial glial cells fail to migrate at all or if the neurons migrate
incorrectly. The cortex will be thickened disorganized. The brain
will not form normal gyri (the folds of the brain). The extreme
example of this is lisencephaly, litterly a smooth ungyrated brain.
Not a good thing.
Not sure if this is what you wanted me to talk about. In what context
did this come up?
Someone was explaining brain development on an autism blog and cited
this paper, among other sources.
http://autismdiva.blogspot.com/2006/02/when-we-were-small-very-small.html
The second commenter said that minicolumns are still somewhat controversial.
So I was wondering what you had to say on the subject. :) Thank you!
Julia
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