A fruit-fly brain playing Doom (simulated fly-brain controller)

Someone built a Doom controller out of a reconstructed fruit-fly nervous system. Live game pixels are turned into inferred retinal inputs, pushed through the retained MaleCNS v1.0 graph, and then translated into fixed game controls. The wiring is huge: 25,582,938 connections and 124,177,617 synaptic contacts. The first test picked four cells after visual-response calibration, while biological walking and mouthpart outputs were left visible only as a comparison — and they were silent.

This is not being sold as a clean fly emulation. It’s a reconstruction with approximate neuron dynamics, not a validated biological model. Some parts are simplified on purpose: graded visual cells are represented with a coarse spiking proxy, retinal geometry and brightness response are assumed, and tonic lamina current is also assumed. The training candidate adds inferred R8 color input, KC adaptation, and modeled chemical modulation, but useful vision is still unvalidated.

The missing and uncertain pieces matter. The graph still has 42 unmapped photoreceptors, and 3,718 transmitter signs are uncertain. Even the source reconstruction is male-only here; female BANC retinal mapping is still unresolved, so this run uses one male reconstruction. That’s a lot of caveat for a project whose charm is precisely that it looks so complete on the screen.

The Doom setup itself is carefully constrained. The arena starts with four ranged monsters, more can spawn every three game seconds up to caps of four imps and four bullet-firing zombies, and ammo boxes refill on contact before returning eight seconds later. Dead monsters also drop ammo, death resets the arena with 100 bullets, and there’s no round timer. The rules are game rules, not fly behaviors.

The clock matters too. One-to-one time keeps simulation time matched to wall time, so Doom slows with the brain and no neural steps are skipped. Everyone watches the same run, nobody can steer it, and the viewer only buffers about 2.5 seconds of actual frames. In other words: a live demo, not a magic trick.