SCIENTISTS INVENT 3D BRAIN

Researchers from Germany and Canada,
who collaborated on the ultra-high
resolution brain model, present their
work in the 21 June issue of the journal
Science.

"The authors pushed the limits of current
technology," said Science's senior editor
Peter Stern about the international
scientific effort. "Such spatial resolution
exceeds that of presently available
reference brains by a factor of 50 in each
of the three spatial dimensions."

The sophisticated modern image
processing methods reveal an
unprecedented look at the very fine
details of the human brain's
microstructure, or cellular level. The
anatomical tool will allow for three-
dimensional cytoarchitectonic mapping of
the human brain and serve as an atlas for
small cellular circuit data, or single layers
or sublayers of the cerebral cortex,
explained the researchers.

Until recently, reference brains did not
probe further than the macroscopic, or
visible, components of the brain. Now,
the BigBrain provides a resolution much
finer than the typical 1 mm resolution
from MRI studies.

The project "has been a tour-de-force to
assemble images of over 7,400 individual
histological sections, each with its own
distortions, rips and tears, into a coherent
3-D volume," said senior author Dr. Alan
Evans, a professor at the Montreal
Neurological Institute at McGill University
in Montreal, Canada. "This dataset allows
for the first time a 3-D exploration of
human cytoarchitectural anatomy."

Thin sections of a 65-year-old human
female brain, which was embedded in
paraffin wax, were cut with a special
large-scale tool called a microtome. Then,
the 20-micrometer thick histological
sections were mounted on slides, stained
to detect cell structures and finally
digitized with a high-resolution flatbed
scanner so researchers could reconstruct
the high-resolution 3-D brain model. It
took approximately 1,000 hours to collect
the data. The resulting images reveal
differences in the laminar pattern
between brain areas.

The new reference brain, which is part of
the European Human Brain Project, serves
as a powerful tool to facilitate
neuroscience research and "redefines
traditional maps from the beginning of
the 20th century," explained lead author
Dr. Katrin Amunts from the Research
Centre Jülich and director of the Cecile
and Oskar Vogt Institute for Brain
Research at the Heinrich Heine University
Düsseldorf in Germany. "The famous
cytoarchitectural atlases of the early
1900's were simplified drawings of a brain
and were based on pure visual analysis of
cellular organization patterns," added Dr.
Amunts.
Because of the sheer volume of this
dataset, the researchers say that there
will be a push by those who want to use
it to develop new and valuable tools for
visualization, data management and
analysis.

"We plan to repeat this process in a
sample of brains so that we can quantify
cytoarchitectural variability," said Dr.
Evans. "We will also integrate this dataset
with high-resolution maps of white
matter connectivity in post-mortem
brains. This will allow us to explore the
relationship between cortical
microanatomy and fiber connectivity,"
said Dr. Amunts.
"We are planning to integrate our
receptor data of the human brain in the
reference frame provided by the
BigBrain," continued senior co-author Dr.
Karl Zilles, who is senior professor of the
Jülich Aachen Research Alliance and
former director of the Cecile and Oskar
Vogt Institute for Brain Research at the
Heinrich Heine University Düsseldorf in
Germany. "We will also transfer high-
resolution maps of quantitative data on
the regional and laminar distribution of
native receptor complexes to the
BigBrain. This will allow us to explore the
relationship between cortical
microanatomy and key molecules of
neurotransmission."
The fine-grained anatomical resolution
will allow scientists to gain insights into
the neurobiological basis of cognition,
language, emotions and other processes,
according to the study. The researchers
also stated that they plan to extract
measurements of cortical thickness to
gain insights into understanding aging and
neurodegenerative disorders; create
cortical thickness maps to compare data
from in vivo imaging; integrate gene
expression data from the Allen Institute;
and generate a brain model with a
resolution of 1 micron to capture details
of single cell morphology.
Public access of the BigBrain dataset will
be provided through the CBRAIN Portal
with free registration, stated the
researchers.