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From:
Meir Weiss <[log in to unmask]>
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Cerebral Palsy List <[log in to unmask]>
Date:
Thu, 29 Mar 2012 19:44:11 -0400
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-----Original Message-----
From: NIH news releases and news items [mailto:[log in to unmask]] On
Behalf Of NIH OLIB (NIH/OD)
Sent: March 29, 2012 16:27
To: [log in to unmask]
Subject: BRAIN WIRING A NO-BRAINER?

U.S. Department of Health and Human Services NATIONAL INSTITUTES OF HEALTH
NIH News National Institute of Mental Health (NIMH)
<http://www.nimh.nih.gov/> Embargoed for Release: Thursday, March 29, 2012,
2 p.m. EDT 


CONTACT: Jules Asher, NIMH Press office, 301-443-4536, <e-mail:
[log in to unmask]>

BRAIN WIRING A NO-BRAINER?  
Scans reveal astonishingly simple 3D grid structure -- NIH-funded study

The brain appears to be wired more like the checkerboard streets of New York
City than the curvy lanes of Columbia, Md., suggests a new brain imaging
study. The most detailed images, to date, reveal a pervasive 3D grid
structure with no diagonals, say scientists funded by the National
Institutes of Health.

"Far from being just a tangle of wires, the brain's connections turn out to
be more like ribbon cables -- folding 2D sheets of parallel neuronal fibers
that cross paths at right angles, like the warp and weft of a fabric,"
explained Van Wedeen, M.D., of Massachusetts General Hospital (MGH), A.A.
Martinos Center for Biomedical Imaging and the Harvard Medical School. "This
grid structure is continuous and consistent at all scales and across humans
and other primate species."

Wedeen and colleagues report new evidence of the brain's elegant simplicity
March 30, 2012 in the journal Science. The study was funded, in part, by the
NIH's National Institute of Mental Health (NIMH), the Human Connectome
Project <http://www.neuroscienceblueprint.nih.gov/connectome/> of the NIH
Blueprint for Neuroscience Research
<http://www.neuroscienceblueprint.nih.gov/>, and other NIH components. 

"Getting a high resolution wiring diagram of our brains is a landmark in
human neuroanatomy," said NIMH Director Thomas R. Insel, M.D. "This new
technology may reveal individual differences in brain connections that could
aid diagnosis and treatment of brain disorders." 

Knowledge gained from the study helped shape design specifications for the
most powerful brain scanner of its kind, which was installed at MGH's
Martinos Center last fall. The new Connectom
<http://projectreporter.nih.gov/project_info_description.cfm?aid=8143497&icd
e=11780526&ddparam=&ddvalue=&ddsub=&cr=5&csb=default&cs=ASC> diffusion
magnetic resonance imaging (MRI) scanner can visualize the networks of
crisscrossing fibers -- by which different parts of the brain communicate
with each other -- in 10-fold higher detail than conventional scanners, said
Wedeen. 

"This one-of-a-kind instrument is bringing into sharper focus an
astonishingly simple architecture that makes sense in light of how the brain
grows," he explained. "The wiring of the mature brain appears to mirror
three primal pathways established in embryonic development." 

As the brain gets wired up in early development, its connections form along
perpendicular pathways, running horizontally, vertically and transversely.
This grid structure appears to guide connectivity like lane markers on a
highway, which would limit options for growing nerve fibers to change
direction during development. If they can turn in just four directions:
left, right, up or down, this may enforce a more efficient, orderly way for
the fibers to find their proper connections -- and for the structure to
adapt through evolution, suggest the researchers. 

Obtaining detailed images of these pathways in human brain has long eluded
researchers, in part, because the human cortex, or outer mantle, develops
many folds, nooks and crannies that obscure the structure of its
connections. Although studies using chemical tracers in neural tracts of
animal brains yielded hints of a grid structure, such invasive techniques
could not be used in humans. 

Wedeen's team is part of a Human Connectome Project Harvard/MGH-UCLA
consortium <http://www.humanconnectomeproject.org/> that is optimizing MRI
technology
<http://www.nimh.nih.gov/science-news/2010/40-million-awarded-to-trace-human
-brains-connections.shtml> to more accurately to image the pathways. In
diffusion imaging, the scanner detects movement of water inside the fibers
to reveal their locations. A high resolution technique called diffusion
spectrum imaging (DSI) makes it possible to see the different orientations
of multiple fibers that cross at a single location -- the key to seeing the
grid structure. 

In the current study, researchers performed DSI scans on postmortem brains
of four types of monkeys -- rhesus, owl, marmoset and galago -- and in
living humans. They saw the same 2D sheet structure containing parallel
fibers crossing paths everywhere in all of the brains -- even in local path
neighborhoods.  The grid structure of cortex pathways was continuous with
those of lower brain structures, including memory and emotion centers. The
more complex human and rhesus brains showed more differentiation between
pathways than simpler species. 

Among immediate implications, the findings suggest a simplifying framework
for understanding the brain's structure, pathways and connectivity.

The technology used in the current study was able to see only about 25
percent of the grid structure in human brain. It was only apparent in large
central circuitry, not in outlying areas where the folding obscures it. But
lessons learned were incorporated into the design of the newly installed
Connectom scanner, which can see 75 percent of it, according to Wedeen.

Much as a telescope with a larger mirror or lens provides a clearer image,
the new scanner markedly boosts resolving power by magnifying magnetic
fields with magnetically stronger copper coils, called gradients.  Gradients
make it possible to vary the magnetic field and get a precise fix on
locations in the brain. The Connectom scanner's gradients are seven times
stronger than those of conventional scanners. Scans that would have
previously taken hours -- and, thus would have been impractical with living
human subjects -- can now be performed in minutes. 

"Before, we had just driving directions. Now, we have a map showing how all
the highways and byways are interconnected," said Wedeen. "Brain wiring is
not like the wiring in your basement, where it just needs to connect the
right endpoints.  Rather, the grid is the language of the brain and wiring
and re-wiring work by modifying it." 

The mission of the NIMH is to transform the understanding and treatment of
mental illnesses through basic and clinical research, paving the way for
prevention, recovery and cure. For more information, visit the
<www.nimh.nih.gov>.

The NIH Blueprint for Neuroscience Research
<http://www.neuroscienceblueprint.nih.gov/> is a cooperative effort among
the NIH Office of the Director and the 15 NIH Institutes and Centers that
support research on the nervous system. By pooling resources and expertise,
the Blueprint supports transformative neuroscience research, and the
development of new tools, training opportunities, and other resources to
assist neuroscientists.


About the National Institutes of Health (NIH): NIH, the nation's medical
research agency, includes 27 Institutes and Centers and is a component of
the U.S. Department of Health and Human Services. NIH is the primary federal
agency conducting and supporting basic, clinical, and translational medical
research, and is investigating the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and its programs,
visit <www.nih.gov>.

 NIH...Turning Discovery into Health
-----------------------------------
REFERENCE:
Wedeen VJ, Rosene DL, Ruopeng W, Guangping D, Mortazavi F, Hagmann P, Kass
JH, Tseng W-YI. The Geometric Structure of the Brain Fiber Pathways: A
Continuous Orthogonal Grid. March 30, 2012 Science.

-----------------------------------

The html version of this release contains images & video at:

http://www.nimh.nih.gov/images/news-items/dsi_scan_monkey_brain_structure.pn
g
Caption: Detail from DSI scan shows fabric-like 3D grid structure of
connections in monkey brain. Source: Van Wedeen, M.D., Martinos Center and
Dept. of Radiology, Massachusetts General Hospital and Harvard University
Medical School

http://www.youtube.com/watch?feature=player_embedded&v=CySDbTH46P4
Caption: Curvature in this DSI image of a whole human brain turns out to be
folding of 2D sheets of parallel neuronal fibers that cross paths at right
angles. This picture came from the new Connectom scanner. Source: Van
Wedeen, M.D., Martinos Center and Dept. of Radiology, Massachusetts  General
Hospital and Harvard University Medical School

##

This NIH News Release is available online at:
<http://www.nih.gov/news/health/mar2012/nimh-29.htm>.

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