A groundbreaking study has provided an unparalleled glimpse into the structural organization of the human brain at the microscale. Using more than 1.4 petabytes of electron microscopy (EM) imaging data, researchers have reconstructed a nanoscale-resolution model of a millimeter-scale fragment of the human cerebral cortex, offering exceptional insights into the brain tissue’s supracellular, cellular, and subcellular levels. The intricacies and complexities of the human brain have long eluded comprehensive understanding, particularly its cellular microstructure and the neural and synaptic circuits it supports, which are instrumental in several brain disorders.
Led by Alexander Shapson-Coe and his team, the study entailed a high-resolution EM reconstruction of a cubic millimeter of the human temporal cortex. This ambitious endeavor resulted in an intricate three-dimensional reconstruction, encompassing approximately 57,000 cells, 230 millimeters of blood vessels, and a staggering 150 million synapses, culminating in a monumental 1,400 terabytes of data. Notably, the reconstruction has led to the identification of previously overlooked aspects of the human temporal cortex, including a higher density of glial cells relative to neurons and the unearthing of rare yet potent axonal inputs housing up to approximately 50 synapses. The team has also developed a user-friendly, open-access tool to visualize and explore this immense dataset, offering a goldmine of potential insights and discoveries for future studies.
In a parallel breakthrough, Harvard researchers, in collaboration with Google’s experts in machine learning, set out to unravel the brain’s enigmatic makeup by reconstructing a wiring diagram of a minute fragment of the human cortex. The meticulous analysis revealed the bewildering complexity and idiosyncrasies of the neural circuitry, cellular connections, supporting cells, and blood supply in this infinitesimal portion of healthy brain tissue.
The collaborative effort involved scrutinizing electron microscope images of over 5,000 slices of the brain tissue, unmasking 57,000 individual cells, an astonishing 150 million neural connections, and an intricate web of 23 centimeters of blood vessels.
This momentous achievement not only offers a comprehensive and intricate understanding of the human brain’s microstructural organization but also lays the foundation for future endeavors to unravel the enigmas enshrouding the brain’s inner workings. The promising insights gleaned from these endeavors may prove to be instrumental in advancing our comprehension of the human brain and ultimately aiding in the development of innovative approaches to address various brain disorders.
