Research2026-09-03

Google Research and HHMI Janelia published a complete wiring map of the male fruit fly's nervous system. It covers the brain and the ventral nerve cord, the insect equivalent of a spinal cord. The map holds over 166,000 neurons and 125 million connections between them. Google calls it the largest brain map yet by neuron count. Human experts at Janelia checked and labelled the automated results. The data can be browsed and downloaded through Neuroglancer, Google's open-source viewer. Pairing it with an earlier female map lets researchers study courtship, aggression and individual variation. Three companion papers on vision, taste and social behaviour appeared the same day. Google also helped map part of an elephantnose fish hindbrain, published in Nature. Verifying such maps still takes years of manual work.

What changed

The largest verified fly map covered half a female brain, with 25,000 neurons.

What it unlocks

Comparing male and female fly nervous systems neuron by neuron, using a free downloadable map.

  • 166,000 neurons mapped
  • 125 million synaptic connections
  • 2020 record: 25,000 neurons

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