Google, HHMI Use AI to Map Male Fruit Fly’s Complete Nervous System

Fruit flies are a mainstay of genetics and neuroscience because their short life cycles and stereotyped behaviors make neural circuits easier to test. A connectome — a wiring diagram of neurons and synapses — can link sensory inputs to motor outputs and behavior. With a full map of the human brain’s roughly 86 billion neurons still beyond current technology, Drosophila offers a tractable model for studying circuit design, brain variation and principles that could inform medicine and more efficient artificial systems.

On Sept. 3, 2026, a consortium led by Howard Hughes Medical Institute’s Janelia Research Campus, with Google Research and other collaborators, published the complete male fruit-fly central nervous system connectome in Cell. AI systems assembled millions of two-dimensional electron-microscope images into three-dimensional neural structures, followed by expert proofreading. The map spans the brain and ventral nerve cord, cataloging 166,691 neurons across 11,691 types and about 125 million synaptic connections. The public dataset lets researchers trace auditory, visual and olfactory signals to motor outputs and compare male and female circuitry at synaptic resolution.