HHMI Janelia, Google Map 166,000-Neuron Male Fruit Fly Brain, Largest Connectome Yet
Updated
Updated · Google Research · Sep 3
HHMI Janelia, Google Map 166,000-Neuron Male Fruit Fly Brain, Largest Connectome Yet
3 articles · Updated · Google Research · Sep 3
Summary
Published in Cell, the new male fruit fly connectome charts more than 166,000 neurons and 125 million synapses across the brain and central nervous system, including the ventral nerve cord.
A decade-long HHMI Janelia-Google effort used AI and human proofreading to turn millions of electron-microscope slices into a verified cellular-scale wiring diagram that researchers can explore and download.
The map complements previously released female fly connectomes, letting scientists compare sex-specific neural differences tied to behaviors such as courtship and aggression and measure individual variability in shared circuits.
The project is part of a broader push to scale connectomics beyond insects, with related fish and zebrafish datasets aimed at revealing brain function and eventually informing studies of disease and neural repair.
Will a 3D wiring map of a fruit fly's nervous system finally unlock the cure for human disorders like Alzheimer's and schizophrenia?
Could the secret to building the ultimate autonomous AI robot be hidden inside the newly mapped brain of a male fruit fly?
If fly behaviors lack a central command hub, what invisible biological forces are truly steering their complex, newly mapped neural networks?
Mapping 139,255 Neurons: The Complete Male Fruit Fly Connectome and Its Impact on Neuroscience, AI, and Human Brain Research
Overview
In June 2026, scientists achieved a historic milestone by mapping the complete adult male fruit fly central nervous system. This was made possible by combining 21 million high-resolution brain images, advanced AI segmentation from Princeton, and a global crowdsourcing effort led by the FlyWire Consortium. The resulting connectome revealed over 139,000 neurons and 50 million synapses, uncovering how genetic factors create sex-specific brain wiring and behaviors. Google’s AI tools dramatically reduced the workload, inspiring even larger projects like the mouse and human brain maps. The open-access connectome now empowers researchers worldwide, driving new discoveries in neuroscience, disease, and artificial intelligence.