Multiple connections have been spotted in mouse brains, though not quite as abundantly as in this human sample. But every so often, researchers spotted cells that connect multiple times, including one pair that were linked by a whopping 19 synapses. Some pairs of cells have slightly more contacts. In the new dataset, about 90 percent of the connections were these one-hit contacts. Usually, most message-sending axons touch a message-receiving dendrite just once. One such curiosity concerns synapses, connection spots where signals move between nerve cells. “When you have large datasets, suddenly these odd things, these weird things, these rare things start to stand out.” Lichtman compares the brain map to Google Earth: “There are gems in there to find, but no one can say they’ve looked at the whole thing.”īut already, some “fantastically interesting” sights have appeared, Lichtman says. “We have really just dipped our toe into this dataset,” says study coauthor Jeff Lichtman, a developmental neurobiologist at Harvard University.

Lichtman Lab/Harvard University, Connectomics Team/Googleįor now, researchers are just beginning to see what’s there. It’s unclear why these cells take these shapes. These two neurons are mirror symmetrical. The full dataset is freely available online. A short description of the resulting view was published as a preprint May 30 to. The sample was then sliced into more than 5,000 wafer-thin pieces and imaged with powerful electron microscopes.Ĭomputational programs stitched the resulting images back together and artificial intelligence programs helped scientists analyze them. After it was removed, the brain sample was quickly preserved and stained with heavy metals that revealed cellular structures. It came from the cortex - the brain’s outer layer responsible for complex thought - of a 45-year-old woman undergoing surgery for epilepsy. Smaller than a sesame seed, the bit of brain was about a millionth of an entire brain’s volume. Scientists at Harvard University, Google and elsewhere prepared and analyzed the brain tissue sample. “In the best possible way, it’s the beginning of something very exciting.” “It’s absolutely beautiful,” says neuroscientist Clay Reid at the Allen Institute for Brain Science in Seattle. This intricate map, named H01 for “human sample 1,” represents a milestone in scientists’ quest to provide ever more detailed descriptions of a brain ( SN: 2/7/14). The map, drawn from a tiny piece of a woman’s brain, charts the varied shapes of 50,000 cells and 130 million connections between them. A new view of the human brain shows its cellular residents in all their wild and weird glory.

Brain neuron connections