Connectomics

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Connectomics^[1] is a new field of neuroscience which aims to analyze every connection between every individual neuron in the brain and eventually the peripheral nervous system. The ultimate product of this burgeoning field will be the brain connectome, a detailed map of every cell and every synapse of the nervous system. The term connectome is meant to directly reference the term genome.

Connectomic research requires a massive amount of tissue to be imaged in great detail. This is achieved by taking brain sections (slices mere nanometers in width) and digitally scanning them with electron microscopy for computerized analysis. Considering the massive scale of such high-throughput research, automation of sectioning and imaging are essential, much as the automation of DNA replication and analysis was crucial in expediting the genome project.

The field of connectomics traces its beginnings to the painstakingly pioneering work of Sydney Brenner, John White and colleagues at the Salk Institute. They mapped the 302 neurons and 7000 synapses in the nervous system of C elegans using electron micrographs. ^[2] Completed in the mid-1980s, the project took a decade to complete.

Today, several research teams are working on that tremendous task. One is lead by Jeff Lichtman at Harvard University's Molecular and Cell Biology department. They are developing the Automatic Tape-collecting Lathe Ultramicrotome, or ATLUM, device. ^[3]

A competing technology is developed by Winfried Denk at Max Planck Institute for Medical Research in Heidelberg. Their Serial Block Face Scanning Electron Microscope, or SBFSEM ^[4], images not the slices cut away by the microtome, but the surface of the remaining tissue block.