A Digital Fly Brain Has Taken Over the Internet

A digital fly brain has been trading bitcoin, parallel parking, exploring bisexuality, cutting doner kebab, playing games—including Minecraft, Doom, and Beat Saber—and generally lighting up social media timelines since it was released earlier this month.

The simulated brain, known as a connectome, is a complete map of more than 166,000 neurons that make up the nervous system of an adult male Drosophila fruit fly. Developed by HHMI Janelia Research Campus in partnership with Google Research, the connectome (dubbed MaleCNS v1.0) was unveiled earlier this month, following the release of the first adult female fruit fly connectome in 2024.

“We present the first finished connectome of an entire male Drosophila central nervous system, encompassing the central brain, optic lobes (analogous to mammalian retina) and the ventral nerve cord (analogous to the spinal cord),” the team announced in a press release on September 3. “Together with existing female connectomes, this resource enables the first comprehensive, synaptic-resolution comparison across sexes of an adult animal with complex anatomy and behaviors.”

The humble fruit fly is a powerhouse species in science for the same reason they might plague your kitchen—they reproduce quickly and are highly adaptable to different environments, distinguishing them as cheap and versatile model organisms. By virtually recreating their brains, researchers aim to make breakthroughs in neuroscience, pharmacology, biotechnology, artificial intelligence, and many other fields.

In the meantime, however, MaleCNS v1.0 has been enthusiastically received by online modders who have dropped the brain into a wide range of virtual environments and tasked it with different activities. Evan Sinclair Smith, a graduate student in computer science at Georgia Tech, pioneered the viral trend after he programmed the fly brain to play Minecraft. Within a day of releasing the results on September 4, the Minecraft fly had accumulated millions of views.

“It’s just been amazing how big this has gotten, and how many other people are just taking this idea and just making so many different creative projects,” Smith told 404 Media in a call. “That’s been just really cool to see.”

In addition to playing video games, the fly has been trained to trade bitcoin (becoming “stonkfly”), write LinkedIn posts, and to retire to a virtual “fruit fly heaven.” Nico Christie, an entrepreneur and AI researcher, programmed the fly to be attracted to other males (becoming “bi fly”).

 In an email, Christie told 404 Media that he came across the trend on X and found it funny, but hoped to make “the science behind it more rigorous.”

In addition to fueling a wave of giddy online experimentation, the connectome has sparked moral and ethical debates on Reddit and other forums. However, it’s worth emphasizing that MaleCNS v1.0 is only a digital map of the brain that is not capable of sentience or conscious perception in any tangible biological sense. The connectome recreates a fly’s neural wirings and overall structure, but it does not contain any of the complex biochemical makeup of the real organism upon which it is based. 

Though the connectome has inspired a literal brain wave of online content, it is intended to be a resource for the scientific community. The female fruit fly brain that was released in 2024, known as FlyWire, has already been used in a host of studies about motor control, sensory systems, fly sociability, and more, according to the neuroscience publication The Transmitter. The completion of both the male and female fruit fly connectomes has also allowed researchers to assess differences in the neural wirings of this sexually dimorphic species.

 Smith, who made the Minecraft fly, hopes that these models will ultimately pave the way toward connectomes of the full human brain within his lifetime. Since the human brain contains 86 billion neurons, orders of magnitude more than the fruit fly brain, it would take an enormous amount of effort to create a digital copy with the same resolution as MaleCNS v1.0 or FlyWire. 

But Smith speculates that such an achievement could unlock new approaches to brain disorders, such as Alzheimer’s disease, or enable human intelligence to navigate space missions without having to haul along our cumbersome meatbag bodies. 

“I think it has so many implications for understanding ourselves,” Smith said.