To understand how the brain’s structure affects various functions, you need a detailed map of the neurons and their connections. Viren Jain of Google Research, Jeff Lichtman of Harvard University, and colleagues made such a map by using volume electron microscopy and advanced computational techniques. The approach’s rapid imaging and automation capabilities made it possible to reconstruct a 1 mm3 volume of tissue from a human brain’s outer layer. The sample had been surgically removed from a patient so that neurologists could reach an underlying region that is a source of epileptic seizures. The volume’s nanoscale resolution is fine enough to make visible individual cellular elements and synapses—the communication sites between neurons—and the encompassed area is large enough to include neural circuits made of tens of thousands of neurons and millions of synapses.
This image shows thousands of neurons whose cell bodies are shaped loosely like pyramids. The neurons...
