A new resource will allow
scientists to explore the anatomy of a single brain in three dimensions at far
greater detail than before, a possibility its creators hope will guide the
quest to map brain activity in humans. The resource, dubbed the BigBrain, was
created as part of the European Human Brain Project and is freely available
online for scientists to use. The researchers behind the BigBrain, at the
Research Centre Jülich and the Heinrich Heine University Düsseldorf in Germany,
imaged the brain of a healthy deceased 65-year-old woman using MRI and then
embedded the brain in paraffin wax and cut it into 7,400 slices, each just 20
micrometers thick. Each slice was mounted on a slide and digitally imaged using
a flatbed scanner.
Many slices had small rips,
tears, and distortions, so the team manually edited the images to fix major
signs of damage and then used an automated program for minor fixes. Guided by
previously taken MRI images and relationships between neighboring sections,
they then aligned the sections to create a continuous 3D object representing
about a terabyte of data. Researchers mentioned that existing three-dimensional
atlases of human brain anatomy are usually limited by the resolution of MRI
images—about a millimeter. The BigBrain atlas, in contrast, makes it possible
to zoom in to about 20 micrometers in each dimension. That’s not enough to
analyze individual brain cells, but it makes it possible to distinguish how
layers of cells are organized in the brain.
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