You competent? doctor has known of myelin problems from your stroke a long time ago, was anything done to solve it? NO? So, pure incompetence in action!
(My
doctor told me I had a bunch of white matter hyperintensities but never
showed me them on any scan, so I don't know the size, location or any
intervention needed, because my doctor knew nothing and did nothing.)
White matter aging and its impact on brain function
Keywords
Introduction
In his pioneering work, De Humani Corporis Fabrica
(1543), Renaissance anatomist Andreas Vesalius provided one of the
earliest descriptions of white matter structure, noting the corpus
callosum as a whitish substance distinct from the softer, yellowish
cerebrum.1
Although Vesalius recognized that the corpus callosum connected the two
hemispheres, he did not understand that its fibers originated from
nerve cell bodies. At the time, white matter was believed to be composed
of excretory ducts filled with a “spongy substance” and was thought to
be the center of spirit and imagination.1
Now, we know that white matter primarily consists of myelinated axons,
glial cells, blood vessels, and extracellular matrix. Oligodendrocytes,
the main cells in white matter, produce myelin sheaths that are crucial
for fast signal transmission and for maintaining the functional and
structural integrity of axons.2,3
Because white matter largely lacks neuronal cell bodies and mainly
serves to connect different gray matter areas, it has not received as
much as attention as the cortical areas of the brain. Yet, its
significance becomes evident when looking at its evolution in primates.
Unlike neocortical gray matter, which grows in direct proportion to
brain size, white matter mass has increased at a much higher rate,
highlighting the crucial role of enhanced connectivity for higher brain
function.4
Consequently, the proportion of white matter in the human brain has
risen to about 40%, with myelinated axons being a major component.4
However, this expansion of white matter also introduces risks,
providing a surface for diseases and the effects of aging. As we age,
our white matter undergoes several changes. It experiences a reduction
in overall volume and exhibits a decline in its microstructural
integrity, and there is an accumulation of focal lesions, contributing
to a decline in cognitive functions and to the risk for age-related
neurological diseases, including dementia and stroke.5,6,7,8 Many of these changes follow non-linear kinetics, starting slowly and then accelerating at a certain age.9
In this context, we explore the structural changes in white matter
associated with aging and investigate the cellular and molecular
mechanisms underlying these age-related transformations. We hypothesize
that chronic inflammation and vascular changes are closely linked to the
degeneration of myelin and axons with age.
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