The fruit fly connectome contains a wide range of information, from cell types and synapses to neurotransmitters and network properties. Here, cells are color-coded by their defining chemical messenger.

Amy Sterling for FlyWire, Princeton University, (Dorkenwald et al., Nature, 2024)

Fruit fly brains are smaller than a poppy seed, but that doesn't mean they aren't complex. For the first time, researchers have published a complete diagram of 50 million connections in an adult fruit flies brain. The journal Nature simultaneously published nine papers related to this new brain map, called a "connectome." Where a genome shows all the genes in a cell or an organism, a connectome shows all the connections between neurons in a brain.

Until now, only a roundworm and a fruit fly larva had been mapped in this way. Fruit fly brains are more complex and need to react to avoid human swats.

Researchers are already hard at work on a connectome of a mouse brain, which has about 1,000 times more neurons than the brain of a fruit fly.

Read more of science correspondent Jon Hamilton's reporting here.

Want to know more about the future of brain science? Email us at [email protected] -- we might cover it on a future episode!

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This episode was produced by Rachel Carlson, edited by Rebecca Ramirez and fact checked by Jon Hamilton. Kwesi Lee was the audio engineer.