The greatest map of all (Image: Bruno Vergauwen)
Our brain is the most complex object in the known universe – so we’ll need to map it in formidable detail to track down memory, thought and identity
A STRANGE contraption, a cross between a deli meat slicer and a reel-to-reel film projector, sits in a windowless room in Cambridge, Massachusetts. It whirs along unsupervised for days at a time, only visited occasionally by Narayanan Kasthuri, a mop-haired postdoc at Harvard University, who examines the strip of film spewing out.
It may seem unlikely, but what’s going on here may revolutionise neuroscience. Spaced every centimetre along the film are tiny dots, each of which is a slice of mouse brain, one-thousandth the thickness of a sheet of aluminium foil. This particular roll of film contains 6000 slices, representing a speck of brain the size of a grain of salt.
The slices of brain will be turned into digital images by an automated electron microscope. A computer will read those images, trace the outlines of nerve cells, and stack the pictures into a 3D reconstruction.
In the jargon, they are building the mouse “connectome”, named in line with the term “genome” for the sequence of all of an organism’s genes, “proteome” for all its proteins, and so on.
It’s an epic undertaking. The full mouse connectome would produce hundreds of times more data than can be found on all of Google’s computers, says Jeffrey Lichtman, the neuroanatomist leading the Harvard team. And yet it’s just the beginning. Their efforts could be seen as a dry run for a project that is at least four orders of magnitude greater: mapping the…
