Neuroscientists
have now identified he critical communications network that supports brain
function- the white matter "scaffold" of the human brain.
Their work,
published Feb. 11 in the open-source journal Frontiers in Human Neuroscience,
has major implications for understanding brain injury and disease. By detailing
the connections that have the greatest influence over all other connections,
the researchers offer not only a landmark first map of core white matter
pathways, but also show which connections may be most vulnerable to damage.
"We
coined the term white matter 'scaffold' because this network defines the
information architecture which supports brain function," said senior
author John Darrell Van Horn of the USC Institute for Neuroimaging and
Informatics and the Laboratory of Neuro Imaging at USC.
"While
all connections in the brain have their importance, there are particular links
which are the major players," Van Horn said.
Using MRI
data from a large sample of 110 individuals, lead author Andrei Irimia, also of
the USC Institute for Neuroimaging and Informatics, and Van Horn systematically
simulated the effects of damaging each white matter pathway.
They found
that the most important areas of white and gray matter don't always overlap.
Gray matter is the outermost portion of the brain containing the neurons where
information is processed and stored. Past research has identified the areas of
gray matter that are disproportionately affected by injury.
But the
current study shows that the most vulnerable white matter pathways - the core
"scaffolding" - are not necessarily just the connections among the
most vulnerable areas of gray matter, helping explain why seemingly small brain
injuries may have such devastating effects.
"Sometimes
people experience a head injury which seems severe but from which they are able
to recover. On the other hand, some people have a seemingly small injury which
has very serious clinical effects," says Van Horn, associate professor of
neurology at the Keck School of Medicine of USC. "This research helps us
to better address clinical challenges such as traumatic brain injury and to
determine what makes certain white matter pathways particularly vulnerable and
important."
The
researchers compare their brain imaging analysis to models used for
understanding social networks. To get a sense of how the brain works, Irimia
and Van Horn did not focus only on the most prominent gray matter nodes - which
are akin to the individuals within a social network. Nor did they merely look
at how connected those nodes are.
Rather, they
also examined the strength of these white matter connections, i.e. which
connections seemed to be particularly sensitive or to cause the greatest
repercussions across the network when removed. Those connections which created
the greatest changes form the network "scaffold."
"Just
as when you remove the internet connection to your computer you won't get your
email anymore, there are white matter pathways which result in large scale
communication failures in the brain when damaged," Van Horn said.
When white
matter pathways are damaged, brain areas served by those connections may wither
or have their functions taken over by other brain regions, the researchers
explain. Irimia and Van Horn's research on core white matter connections is
part of a worldwide scientific effort to map the 100 billion neurons and 1,000
trillion connections in the living human brain, led by the Human Connectome
Project and the Laboratory of Neuro Imaging at USC.
Irimia notes
that, "these new findings on the brain's network scaffold help inform
clinicians about the neurological impacts of brain diseases such as multiple
sclerosis, Alzheimer's disease, as well as major brain injury. Sports
organizations, the military and the US government have considerable interest in
understanding brain disorders, and our work contributes to that of other
scientists in this exciting era for brain research."
Source : medindia.net
No comments:
Post a Comment