In a landmark step, scientists trace full wiring diagram of the fly brain’s core

SIMULATION SHOWING MAJOR CIRCUITS IN THE CENTRAL REGION OF THE FRUIT FLY BRAIN, WHOSE “CONNECTOME” SCIENTISTS HAVE MAPPED. (JANELIA RESEARCH CAMPUS/HOWARD HUGHES MEDICAL INSTITUTE)

Scientists just announced that they had mapped 25,000 neurons and 20 million synapses in the central part of the fruit fly brain, in what’s known as a “connectome.” A team at the Janelia Research Campus of the Howard Hughes Medical Institute did the electron microscopy, while a Google team developed algorithms to interpret the images so as to trace the path of every neuron. The project has taken upward of $40 million and 12 years, though progress sped up so much at the end that the entire fruit fly connectome should be finished in two years. The neural map promises to illuminate the brain pathways that underlie perception, memory, and behavior in insects and perhaps mammals, and could pave the way for a mouse connectome and even, eventually, a human connectome (with 86 billion neurons, and trillions of synapses).