Is the intention that terms such as 'White matter of diencephalon' refer to a single thing which is the sum of all white matter that is part of the diencephalon, or is it the intention that it be the type of any little piece of white matter that is part of the diencephalon.
The documentation for white matter of the neuraxis suggests the second interpretation.
OM: 1. gray matter is a cluster of neural somas while white matter is a cluster of neurites (axons and/or dendrites). In both cases, it's a collection of cell parts plus intervening connective tissue and vasculature. n2. this is a semantic class; it does not represent the entire white matter as one whole unit.
However a couple of things struck me. "
1) In the definition of the forebrain white and gray matter are constitutional parts
'Forebrain' :IS-A 'Cardinal segment of brain'
'constitutional part' 'Gray matter of forebrain')
'constitutional part' 'White matter of forebrain')
'regional part' 'Diencephalon')
'regional part' 'Telencephalon')
'definition' "Organ component of neuraxis that has as its parts the
telencephalon, diencephalon, lateral ventricles and third
ventricle. Examples: There is only one forebrain."))
2) It seems clear that *some* subclasses are intended to be sums
'Gray matter of left hippocampus proper' :IS-A 'Gray matter of hippocampus proper'... 'Gray matter of neuraxis'
'constitutional part of' 'Left hippocampus proper'
'constitutional part' 'Ependyma of left hippocampus proper'
'constitutional part' 'Pyramidal layer of left hippocampus proper'
'constitutional part' 'Radiate layer of left hippocampus proper'
'constitutional part' 'Oriens layer of left hippocampus proper'
'constitutional part' 'Lacunar-molecular layer of left hippocampus proper'
3) It looked a little odd that e.g. White matter of thalamus has part Neuroglial network of white matter of diencephalon. But this is just going on names.
'White matter of diencephalon' :IS-A 'White matter of neuraxis'
'constitutional part of' 'Diencephalon'
'constitutional part' 'Neuroglial network of white matter of diencephalon'
'constitutional part of' 'Neural tissue of diencephalon'
:SUBCLASSES ('White matter of subthalamus'
'White matter of epithalamus'
'White matter of thalamus'
'White matter of hypothalamus'
'Capsule of diencephalon')
In general there seems to be a few hierarchies that parallel some amount of the part structure of the brain and I'm having some trouble keeping track of the purpose of it all - there's the White/gray matter of xxx, Set of xxx, Segment of xxx, Neural tissue of xxx, ....
-Alan