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The human brain is a complicated organ made up
of networks of neurons used to transmit signals
back and forth.
In simple terms, it is the organ responsible for telling
the body what to do and when to do it.
In an ongoing attempt to further understand just
how the brain operates, scientists
have been trying to chart the connectivity and functions
of neurons in the brain, a task that is as fascinating as it
is challenging.
Now with a new method developed at MIT,
researchers have a new way to image brain tissue
at not just one, but at multiple scales,
allowing them to peer at molecules within cells
or take a wider view of the long-range connections
between neurons.
Their new technique, known as Magnified Analysis of Proteome,
or MAP, uses a chemical process to expand tissue samples
while preserving all of the proteins within the cells
down to the nanoscopic details.
Their technique relies on flooding the brain tissues
with acrylamide monomers, which are attached to the proteins
using formaldehyde.
The researchers then link the monomers together
into a dense, naturally expandable gel.
Once proteins are denatured and separated,
the gel expands the tissue sample
to four or five times its original size.
Once the tissue is expanded, the researchers
used an off-the-shelf antibody to fluorescently tag
specific proteins they'd like to image.
Then, using a microscope, the researchers
are able to obtain images with a resolution as high as 60
nanometers, much better than the usual 200 to 250
nanometer limit of light microscopes,
which are constrained by the wavelength of visible light.
The researchers also showed that the technique
is applicable to other organs such as the heart, lungs,
liver, and kidneys.
Current efforts to map the connections of the brain
rely on electron microscopy, or low resolution light
But this team of MIT researchers have demonstrated
that the high resolution MAP imaging
technique can trace neural connections easily and more