Write your abstract here.‘Virtual’ mouse brains now
available online.
A
multi-institutional consortium
including Duke University has created
startlingly crisp 3-D microscopic views of tiny mouse brains — unveiled
layer by layer — by extending the capabilities of conventional magnetic
resonance
imaging.
“These
images can be more than 100,000 times higher resolution than a clinical
MRI scan,” said G. Allan Johnson, Duke’s Charles E. Putman
Distinguished Professor of radiology and professor of biomedical
engineering and physics. He is first author of a report describing the
innovations set for publication in the research journal NeuroImage. View it online
Images on the website for Duke’s Center for In Vivo Microscopy http://www.civm.duhs.duke.edu/,
which Johnson directs, reveal examples of these innovations in action.
In one video two different mouse brains — one from a normal animal and
the other from a rodent missing a gene linked to mental abnormalities —
seem to assemble themselves before the viewer’s eyes, structure by
structure.
Watch the video with Johnson at http://realmedia.oit.duke.edu/ramgen/news/brain_imaging.rm (RealMedia) orhttp://quicktime.oit.duke.edu/news/brain_imaging.mov (Quicktime).
After
building up like time-lapse photos of opening flowers, the side-by-side
brain images begin revolving as overlying tissues dissolve into
computer-rendered transparency. What remains visible, seemingly
floating over the bases of the animals’ skulls, are two color-coded
brain structures — the ventricles and hippocampus — showing different
volumes resulting from specific genetic differences.
Under
funding from the National Center for Research Resources, the new
imaging technologies are being developed and shared by six institutions
that form the Mouse Bioinformatics Research Network (MBIRN).
Those
six schools — Duke, the California Institute of Technology, the
University of Tennessee at Memphis, the University of California at Los
Angeles, Drexel College of Medicine and the University of California at
San Diego — are connected via a very high speed network with each other
as well as with the San Diego Supercomputing Center.
The
consortium has developed the computer infrastructure to collect a
rapidly growing library of 3-D mouse brain data, and make all the data
available on the web http://tinyurl.com/3cgj6z.
The goal is to use mouse brains as surrogates for human brains to study
the connections between genes and brain structure. Investigators from
all over the world are sending their models to Duke where the 3-D
images are acquired in a standardized fashion and made available via
high speed web connections.
High
resolution magnetic resonance imaging — which the researchers call “MRI
histology” provides distortion-free 3-D images with superb ability to
distinguish subtle tissue differences in the brain, according to
Johnson.
“The
specimen is still actually in the skull,” he said. “It hasn’t been cut
by a knife. It has not been dehydrated and distorted as it would be in
conventional histological techniques.”
Using
computer-guided statistical methods, the data can be segmented into
more than 30 anatomical structures with quantitative volume
measurements. These structures can then be computer-enhanced to produce
color-coded and labeled volume renderings of selected anatomical
details in 3-D, seen at any angle.
MRI
scanning is also quicker and costs less than conventional histology, he
said. MRI histology permits study of an entire brain, which would be
prohibitively expensive using conventional methods.
The
Duke center has pioneered the development of MRI microscopy to image
the micro-anatomies of small biological specimens. The NeuroImage study
describes the ways his group have devised to manipulate the signals to
achieve varieties of contrasts and resolutions.
For
instance, the technology can discriminate grey matter from the white
matter within mouse brains. “We have the ability to highlight soft
tissue differences with extraordinary clarity,” Johnson said.
Source: Duke University