Scientists mapped a fragment of the human brain

Researchers publish largest-ever dataset of neural connections.


Harvard and Google researchers have created the largest synaptic-resolution, 3D reconstruction of a piece of human brain to date. In striking clarity, their work displays every cell and the network of connections between them in a half-rice-grain-sized section of the human temporal cortex.

Scientists combined Lichtman’s electron microscopy imaging with AI algorithms to color-code and reconstruct the extremely complex wiring of mammal brains.

Scientists wanted to create a high-resolution map of the neural wiring of a whole mouse brain, which would require about 1,000 times the data they just produced from the 1-cubic-millimeter fragment of the human cortex.

Jeff Lichtman, the Jeremy R. Knowles Professor of Molecular and Cellular Biology and newly appointed dean of Science, said, “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,” Lichtman said. “A terabyte is, for most people, gigantic, yet a fragment of a human brain – just a minuscule, teeny-weeny little bit of human brain – is still thousands of terabytes.”

An unusual yet potent group of axons connected by up to 50 synapses is among the never-before-seen features of the brain’s structure found in the most recent map published in Science. The group also saw anomalies in the tissue, like a few axons forming large whorls. Since the patient from whom their sample was obtained had epilepsy, they are unaware of the rarity or pathology of these unique forms.

Like genomes, Lichtman’s field of study, “connectomics,” aims to produce thorough catalogs of the brain’s anatomy down to the individual cells and wiring. Completing these maps would pave the path for novel understandings of brain function and illness, which scientists now know very little about.

Thanks to Google’s advanced algorithms, scientists could reconstruct and map brain tissue in three dimensions. Researchers also developed a suite of publicly available tools to examine and annotate the connectome.

Google Research collaborator Viren Jain said“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.”

Journal Reference:

  1. Alexander Shapson-Coe, Michal Januszewski, Daniel Berger, et al. A petavoxel fragment of human cerebral cortex reconstructed at nanoscale resolution. Science. DOI: 10.1126/science.adk4858


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