Researchers at Google and the Howard Hughes Medical Institute published a complete brain and central nervous system map of an adult male fruit fly on September 3, 2026. Containing over 166,000 neurons and 125 million synapses, the connectome has quickly been repurposed by software engineers to run classic video games like Doom.
Scientists completed a decade-long project to map the entire neural network of an adult male fruit fly. Announced by Google Research and the Howard Hughes Medical Institute’s Janelia Research Campus, the achievement delivers the largest brain map by number of neurons to date. The resulting wiring diagram, known as a connectome, catalogs over 166,000 neurons and 125 million synaptic connections, providing a fundamental resource for scientists to use fruit flies as a model organism for studying how the brain works.
Scientists have been using fruit flies for research for over a century, building a strong history in the avenues of genetic research. Working alongside HHMI Janelia Research Campus and the scientific community, Google Research scientists used AI to combine millions of 2D images into 3D neural shapes, reconstructing a record-breaking 166,000+ neurons. Researchers created it by slicing the nervous system into millions of extremely thin sections, imaging them with an electron microscope, and then using computers and AI to turn those 2D images into 3D reconstructions of neurons. Scientists then spent years verifying and annotating the results.
Google says that because mapping the roughly 86 billion neurons in a human brain is not possible yet, scientists are starting with smaller organisms like fruit flies. The project aims to help scientists learn how animal nervous systems perceive the world, react to stimuli, and how damaged neural pathways might one day be repaired.
Software Engineers Train Simulated Fly Brains to Play Doom
Within days of the map’s public release, programmers began using the MaleCNS v1.0 data to power simulated environments. On Monday, software engineers were already demonstrating the full MaleCNS v1.0 fruit fly connectome being trained to play Doom, as well as Super Mario 64. Software engineer Alex Wormuth demonstrated a setup where a virtual fly brain attempts to play Doom.
“Each Doom frame stimulates sensory neurons. Neural activity is mapped to game controls. Damage triggers a stimulus to two PPL101 dopamine cells as reinforcement.”
Alex Wormuth, Software Engineer
Wormuth posted on Sept. 6 that he is using the project’s data to train a simulated fly brain to play Doom, closing a post on X with the question Will the fly learn to survive?
The code is fully open source, and the project is being livestreamed online so viewers can watch the training progress of the 166,700 neurons live. Developer Jessica Paquette also posted Monday about a similar project using the fly brain data to play Super Mario 64. Paquette, described as a ‘C++ ragebaiteur’, shared a video showing Mario jumping and repeatedly bumping into walls. Paquette also posted the project’s code on GitHub, where she wrote that the code is literally 100% vibe coded with GPT Astra… just for fun.
Broader Experiments and Future Connectome Mapping
Beyond video games, the open-source neural data sparked varied digital tests. One X user said he fine-tuned the simulated fly brain to make Y-M-C-A poses in response to four different tones. And another user made the simulated fly brain watch the viral Bad Apple!! animation to see how it reacted. Yet another user wrote on X that they successfully ran the full retained MaleCNS v1.0 fruit fly connectome, all 166,700 neurons, inside Minecraft, with its simulated neural activity driving a fly’s movement. These fast community adaptations highlight how open scientific datasets rapidly find unexpected applications in hobbyist programming.
Google described the milestone as a major milestone in neuroscience that is going to accelerate our understanding of the brain. As researchers continue analyzing the fruit fly data, Google is already looking beyond flies and is working with researchers on connectomes for fish and mice.
