Male Fruit Fly Brain Trained to Play Doom

Last week, Google announced that it managed to produce a detailed 3D reconstruction of an adult male fruit fly's brain and central nervous system. A few days later a software engineer at Coinbase said the fly brain was being trained to play the original Doom. "Each Doom frame stimulates sensory neurons," says Alex Wormuth. "Neural activity is mapped to game controls. Damage triggers a stimulus to two PPL101 dopamine cells as reinforcement." Since then, the digital brain model has been repurposed to control other games like Beat Saber and Super Mario 64. PC Gamer reports: You can even watch the fruit fly play in real time via Wormuth's website, and it not only shows the point of view in Doom, but can also show a third-person render of the fly going around Doom maps. As of the time of writing, the fly is on round 6385 and, well, it's not very good. Sorry, fly. But modders aren't done here. They have also somehow managed to make the fruit fly play Beat Saber, and play it pretty well. Lyra Bubbles on X has used the brain and replays of a song in Beat Saber to teach the fruit fly where to hit and why, via Reinforcement Learning. That does mean it's not organically reacting to the notes popping up on screen, but it is receiving input and responding to stimuli. Lyra says, "Further training is to reduce reliance on external signals and allow it to play fully reactively with no input data." And, after "pivoting to fly engineering in 2026", Jessica Paquette also shared on X their experience running the digital fly brain through Super Mario 64. If you think that is all the game's modders made the fruit fly play, think again, as YouTuber Ro0oney even put it in Minecraft. But this time, Ro0oney used Flywire.AI, a similar project made in collaboration with Princeton University. The number of neurons are different (160,000+ vs 139,255), and Google analyzed a male brain whilst Flywire analyzed a female brain, but the basic idea is the same.