In article <1992May18.060418.18022 at yang.earlham.edu> allens at yang.earlham.edu (Allen Smith) writes:
-->> Then they said that the cells are white or gray depending on
-->> whether or not there are myelinated sheaths.
-->> I found the part about the right being myelinated and the left
-->> being unmyelinated hard to believe. Could anyone clarify or
-->> explain the areas of the human brain that are/aren't myelinated?
--> I believe the myelination state, at least in the cerebrum, depends
-->on whether the area is the interior or the exterior. The outer layer is
-->the reverse of the inner. However, I can't remember which is which.
Speaking grossly, the areas of the brain which contain cell bodies are
not as myelinated and are called gray matter. Axons are often
myelinated, and areas with many myelinated axons appear white in
fresh brains, hence they are called white matter. The clearest
distinction between white and grey matter is in the forebrain, e.g.
cerebral cortex (=grey matter) and the white matter underlying it.
In most other parts of the brain, such as the brainstem, the amount of
myelination is intermediate.
e-mail: tbd at neuro.duke.edu
Department of Neurobiology, Duke University Medical Center
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