Scientists complete male fruit fly brain map

A brain as small as a fruit fly’s can still contain hundreds of millions of synapses—and mapping them is a job no human team could finish in a manageable time. Researchers at the Howard Hughes Medical Institute’s Janelia Research Campus and Google have now completed a map of every neuron in a male fruit fly brain.

The result is a connectome, a map intended to show the brain’s complete neural organization. To produce it, the team had to prepare an entire brain for imaging at the necessary resolution, then interpret what those images indicated. Each stage demanded different expertise: Janelia supplied biologists, while Google supplied computer scientists, and the two groups say neither could have completed the project without the other.

The map is more than an inventory. Researchers expect the connectome to become a valuable tool for understanding how the brain works, with the potential to accelerate neurobiology research. It also gives scientists an opportunity to do research on the connectome itself, rather than treating the map only as a record.

That opportunity is strengthened by a female Drosophila connectome completed earlier this year. The new male map now provides a second complete fruit fly brain map for researchers to study alongside it, although the source does not specify what findings that comparison has produced.

So, concretely, neurobiologists gain a finished reference that could make brain research faster and more systematic. The broader path is still open rather than completed: the team refined tools likely to be applied to increasingly complex nervous systems, potentially including vertebrates, but no vertebrate connectome is reported here.