One man’s neuron is another man’s knowledge. That’s the stance of the Allen Institute for Brain Science, which this week released the first open-access database of live human brain cells. It contains data on the electrical properties of about 300 cortical neurons taken from 36 patients and 3D reconstructions of 100 of those cells, plus gene expression data from 16,000 neurons from three other patients. Working with Seattle, Washington–area neurosurgeons, the Allen Institute acquired healthy cells from the cortex—the outermost layer of the brain that coordinates perception, memory, thoughts, and consciousness—from patients undergoing surgery for epilepsy or brain tumors. Normally considered medical waste, these tissues can now provide scientists with a unique resource for understanding the human brain. That’s because most studies on single human brain cells use dead rather than living tissue, and many others rely on cells from common laboratory animals, especially mice. The new data should help researchers pin down what makes human brains unique from other species—and what makes for a healthy versus diseased brain.