What it is
The FlyWire consortium, led by Princeton, published the first complete connectome of an adult Drosophila brain: every one of its 139,255 neurons and the roughly 50 million synapses between them, reconstructed from electron-microscopy images and sorted into more than 8,400 cell types. Before this, complete connectomes existed only for animals with a few hundred to a few thousand neurons (the worm, the sea squirt and the comb jelly). It is the reference map every later fly-brain connectome, including the complete male nervous system, is aligned against.
Why it matters
A whole-brain connectome turns the fly brain from a set of separately studied circuits into one navigable map, where any neuron can be traced to everything it connects to. It made possible full accounts of the circuits for vision, navigation and learning, and it is the baseline against which differences (between individuals, and between the sexes) can be measured at the level of single synapses.
Underlined numbers link to their source. Every metric and quoted figure is listed under Sources and data below.
Filed underconnectome, drosophila, whole-brain, electron microscopy, neuroscience