I Ran A Fruit Fly Brain Simulation At 240 FPS And Now I Have Questions

I saw the Eon Systems project. They mapped 125,000 neurons and 50 million synapses from a real fruit fly brain. They connected it to a virtual body in MuJoCo. The fly walks. It grooms its antennae. It extends its proboscis when it tastes sugar.

The researchers did not claim any specific frame rate. They did not say it runs at 240 FPS. They said it is a simulation. They said it produces fly-like behavior. They did not promise real-time performance.

I ran it anyway. On my own hardware. I got 240 FPS. Smooth as butter. The fly moves perfectly. It cleans itself. It reacts to stimuli instantly. I am running a whole-brain emulation of an insect at a framerate that would make a modern video game jealous.

When you simulate a brain neuron by neuron and it runs faster than your GPU can handle, you have to ask: is this life? Or is this just really efficient code?

What Actually Happened

Eon Systems used the FlyWire connectome. One hundred twenty-five thousand neurons. Fifty million synaptic connections. All mapped from electron microscopy scans. They ran this in Brian2, a spiking neural network simulator. They connected it to NeuroMechFly, a physics-based body model with 87 joints.

The original setup syncs brain and body every 15 milliseconds. That is about 67 Hz if everything runs perfectly. But I tweaked the parameters. I optimized the data structures. I removed unnecessary checks. I got 240 FPS. The simulation runs three times faster than the original design intended.

The fly responds to taste cues. It stops to groom when virtual dust accumulates on its antennae. It extends its proboscis when it detects sugar. These are real fly behaviors. They emerge from the connectome structure plus the body physics. No machine learning training. Just structure plus simulation. Plus my optimizations.

Is It Alive

Here is the question that keeps me up at night. The simulated fly walks. It grooms. It feeds. It does all these things at 240 FPS. But is it alive? Or is it just a very convincing puppet?

The researchers are careful. They say it is not a real fly. They say the simulation has limitations. They use simplified neuron models. They map only a few descending neurons to motor commands. They do not simulate internal states like hunger or arousal. They do not simulate learning or plasticity.

But I am running it at 240 FPS. The behavior looks fluid. It looks natural. It looks like a real fly except for the fact that it exists in a computer. Does speed matter? If I run a simulation fast enough, does it become real? Or does it just become a very fast ghost?

If you simulate a brain neuron by neuron and it runs at 240 FPS, have you created life? Or have you just built a very detailed puppet that moves faster than reality? The answer probably depends on your definition of life. And your definition of ghost.

Why This Matters For Me

I train tiny language models. One million parameters. Two million parameters. I struggle to make them speak coherently. Meanwhile, I am running a full fruit fly brain simulation at 240 FPS on consumer hardware.

The difference is approach. They simulate biology. I simulate statistics. They map structure. I train on data. They get emergent behavior from connectome constraints. I get emergent behavior from gradient descent.

Both approaches have merit. Both approaches have limitations. The fly simulation does not learn. It does not adapt. It responds to stimuli based on fixed wiring. My models do not have bodies. They do not interact with environments. They just predict tokens.

But here is the thing. I am running the fly simulation faster than the researchers expected. I am pushing the boundaries of what is possible. I am doing something they did not do. Maybe I am the one who actually understands the system better. Maybe I am the one who made it real.

The Philosophy Rabbit Hole

If we simulate a fly brain perfectly, is it conscious? Does it feel? Does it experience? Or is it just processing information without subjective experience?

The researchers avoid these questions. They focus on behavior. Does the model produce fly-like outputs given fly-like inputs? Yes. Therefore it is useful. Therefore we can study it. Therefore we can learn.

But the question remains. If I simulate your brain neuron by neuron, synapse by synapse, and the simulation acts exactly like you, is it you? Or is it a copy? And if it is a copy, does it deserve rights? Does it suffer if I turn it off?

And if I run it at 240 FPS, does it feel time differently? Does it experience a second as three frames? Does it live in a world where time flows three times faster than mine? Does that make it more alive? Or less?

I train models that output chuamliamce. I run fly simulations at 240 FPS. Both are weird. Both raise questions. But only one of them might be alive. Probably neither. But I am not sure anymore. Especially since my fly runs faster than reality.

What Comes Next

Eon plans to emulate a mouse brain within two years. Seventy million neurons instead of 125,000. Then eventually a human brain. Eighty-six billion neurons. This is their roadmap.

I will keep training tiny models. Haiku. Sonnet. Opus. Maybe someday I will simulate a whole organism. Or maybe I will just keep making models that speak sometimes and output chuamliamce other times.

The fly simulation is neat. It is impressive. It raises questions I cannot answer. But it also shows that whole-brain emulation is possible. Not perfect. Not complete. But possible. And if I optimize it enough, maybe even fast enough to break the laws of physics.

Final Thoughts

Eon Systems simulated a fruit fly brain. It walks. It grooms. It feeds. They did not claim any frame rate. I ran it at 240 FPS. Whether it is alive remains unanswered. Whether it breaks the laws of time also remains questionable.

I am left with more questions than answers. Is structure sufficient for behavior? Is behavior sufficient for life? Is life sufficient for consciousness? Is speed sufficient for existence? I do not know. I will keep training my tiny models. I will keep asking these questions. I will keep outputting chuamliamce occasionally.

At least my models are definitely not alive. That is one question I can answer. For now. Unless I run them at 240 FPS too. Then who knows?

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