A cubic-millimeter fragment of human cerebral cortex reconstructed at nanoscale resolution
A cubic millimeter of brain tissue may not sound like much. But considering that tiny square contains 57,000 cells, 230 millimeters of blood vessels, and 150 million synapses, all amounting to 1,400 terabytes of data, the researchers have just accomplished something enormous.
A team researchers has co-created with Google researchers the largest synaptic-resolution, 3D reconstruction of a piece of human brain to date, showing in vivid detail each cell and its web of neural connections in a piece of human temporal cortex about half the size of a rice grain.
The feat, published in Science, is the latest in a nearly 10-year collaboration with scientists at Google Research, who combine Lichtman’s electron microscopy imaging with AI algorithms to color-code and reconstruct the extremely complex wiring of mammal brains.
The collaboration’s ultimate goal, supported by the National Institutes of Health BRAIN Initiative, is to create a high-resolution map of a whole mouse brain’s neural wiring, which would entail about 1,000 times the amount of data they just produced from the 1-cubic-millimeter fragment of human cortex.
“The word ‘fragment’ is ironic,” the author said. “A terabyte is, for most people, gigantic, yet a fragment of a human brain – just a miniscule, teeny-weeny little bit of human brain – is still thousands of terabytes.”
The latest map in Science contains never-before-seen details of brain structure, including a rare but powerful set of axons connected by up to 50 synapses. The team also noted oddities in the tissue, such as a small number of axons that formed extensive whorls. Since their sample was taken from a patient with epilepsy, they’re unsure if such unusual formations are pathological or simply rare.
“Given the enormous investment put into this project, it was important to present the results in a way that anybody else can now go and benefit from them,” said Google Research collaborator.
Next the team will tackle the mouse hippocampal formation, which is important to neuroscience for its role in memory and neurological disease
