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? _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
