Connectomics Study Maps Cells and Circuits of Human Temporal Cortex Fragment

A collaboration between Harvard and Google researchers has resulted in the creation of a large synaptic-resolution, 3D reconstruction of a fragment of human brain tissue. This achievement, published in Science, unveils the intricate details of the tiny human temporal cortex sample, about half the size of a rice grain, revealing the staggering complexity within.

Despite its minuscule size, this cubic millimeter of brain tissue contains 57,000 cells, 230 millimeters of blood vessels, and 150 million synapses, amounting to 1,400 terabytes of data. The team, led by Harvard's Jeff Lichtman, combined cutting-edge electron microscopy imaging with Google's AI algorithms to color-code and reconstruct the intricate neural wiring of this mammalian brain sample.

The collaboration's ultimate goal, supported by the National Institutes of Health BRAIN Initiative, is to create a high-resolution map of an entire mouse brain's neural wiring, a monumental task that would entail processing approximately 1,000 times the amount of data they've just produced from this human cortex fragment.

The latest map in Science unveils never-before-seen details of brain structure, including rare and powerful axons connected by up to 50 synapses, as well as unusual formations like extensive axonal whorls. While the sample was taken from an epilepsy patient, the researchers are unsure if these oddities are pathological or simply rare occurrences. 

This ongoing connectomics research aims to create comprehensive catalogues of brain structure, down to individual cells and wiring, paving the way for new insights into brain function and disease. The team also developed a suite of publicly available tools researchers can use to examine and annotate the connectome.