Wednesday, January 30, 2008

Connectomics

Harvard scientists have embarked upon an ambitious program to create a circuit diagram of the human brain, with the help of new machines that automatically turn brain tissue into high-resolution neural maps.

By mapping every synapse in the brain, researchers hope to create a "connectome" -- a diagram that would elucidate the brain's activity at a level of detail far outstripping today's most advanced brain-monitoring tools like fMRI.

The effort is part of a new field of scientific research called connectomics. The field is so new that the first course ever taught on it recently ended at MIT. It is to neuroscience what genomics is to genetics. Where genetics looks at individual genes or groups of genes, genomics looks at the entire genetic complement of an organism. Connectomics makes a similar jump in scale and ambition, from studying individual cells to studying swaths of the brain containing millions of cells. A full set of images of the human brain at synapse-level resolution would contain hundreds of petabytes of information, or about the total amount of storage in Google's data centers, Lichtman estimates.

Lichtman's lab is creating what could be the equivalent of the genome sequencing machine, which dramatically sped up the race to map the human genome. It's an automated brain peeler and imager they call ATLUM.

ATLUM uses a lathe and specialized knife to create long, thin strips of brain cells that can be imaged by an electron microscope. Software will eventually montage the images, creating an ultrahigh-resolution 3-D reconstruction of the mouse brain, allowing scientists to see features only 50 nanometers across.

While connectomics researchers are very excited, they're still just getting a handle on mouse-sized brains. It could be a decade before data-crunching technology will be available to map the complexity of the human brain.
via Wired

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