First complete map of a male fruit fly's nervous system: 166,000 neurons and 125 million synapses

Researchers on September 3 published in Cell the first complete map of the central nervous system of a male fruit fly (Drosophila melanogaster), with more than 166,000 neurons and some 125 million synaptic connections.

The map, known as a connectome, links the brain to the nerve cord that controls the legs and wings, showing for the first time the full path from perception to movement in one animal. Google's AI traced the neurons in electron-microscope images, and researchers at HHMI's Janelia campus checked and corrected the results.

The largest map so far

Google called it "the largest brain map by number of neurons to date". An earlier connectome of a female fly covered only the brain, without the nerve cord.