Using more than 1.4 petabytes of electron microscopy (EM) imaging data, researchers generated a nanoscale-resolution reconstruction of a millimeter-scale fragment of human cerebral cortex, providing an unprecedented view into the structural organization of brain tissue at the supracellular, cellular, and subcellular levels. ⁠ ⁠ The human brain is a vastly complex organ and, to date, little is known about its cellular microstructure, including the synaptic and neural circuits it supports. Disruption of these circuits is known to play a role in myriad brain disorders. Yet studying human brain samples in such great detail comes with a host of challenges, ranging from technological limitations to the availability and preservation of tissue samples from healthy individuals. ⁠ ⁠ In a 2024 Science study, researchers performed a high-resolution EM reconstruction of the ultrastructure of a cubic millimeter of human temporal cortex. According to the authors, the reconstruction contains roughly 57,000 cells, about 230 millimeters of blood vessels, and nearly 150 million synapses, comprising 1400 terabytes of data. The authors generated a three-dimensional reconstruction of nearly every cell and process in the cubic millimeter sample and developed a freely available tool for visualizing and analyzing the vast dataset.⁠ ⁠ Learn more on #WorldBrainDay: scim.ag/41z2OJ4