Skip to Content
Biotechnology

This map of a fly’s brain connectivity is the best we’ve ever seen

January 23, 2020
A map of a fruit fly's hemibrain
A map of a fruit fly's hemibrainFlyEM | Janelia Research Campus

The news: Researchers from Google and Janelia Research Campus in Virginia have unveiled the biggest high-resolution map of brain connectivity yet, known as a connectome. It shows a diagram of a fruit fly’s brain, containing 25,000 neurons and the 20 million connections between them. More images can be viewed here.

What does it show? The map shows a region of the fly’s brain that is about 250 micrometers across, equivalent to the thickness of two strands of hair. The mapped area accounts for about a third of the fly’s total brain, and it contains regions associated with memory and navigation. A pre-print paper describing the research is available on bioRxiv, and the team has made the data available for anyone to view and download.

How it was made: Once the fruit fly brain had been sliced into very thin sections, the slices were scanned using an electron microscope. That produced 50 trillion 3D pixels, which were processed using an algorithm to trace each cell’s pathways. Despite Google’s computing muscle, the project still required a lot of manual labor to proofread the data.

The context: It’s a landmark for neuroscientists, who would love to be able to connect areas of the brain to specific behaviors. Before now, the only animal to have its brain fully mapped was the C. elegans roundworm, which only has about 302 neurons. The publication of a draft of the worm's connectome in 1986 has led to some useful insights into how certain neurons relate to behaviors, such as how they respond to temperature. But not all neuroscientists are convinced that brain mapping in this way (connectomics, as it's known) is the best use of resources. For one thing, a connectome cannot show how an animal's neurons fire in real time.

What about humans? We’re still a very long way from creating a complete connectome of the human brain. Fruit flies’ brains contain nearly 100,000 neurons. Human brains have about 86 billion.

Sign up here to our daily newsletter The Download to get your dose of the latest must-read news from the world of emerging tech. 

Deep Dive

Biotechnology

These scientists used CRISPR to put an alligator gene into catfish

The resulting fish appear to be more resistant to disease and could improve commercial production—should they ever be approved.

Next up for CRISPR: Gene editing for the masses?

Last year, Verve Therapeutics started the first human trial of a CRISPR treatment that could benefit most people—a signal that gene editing may be ready to go mainstream.

CRISPR for high cholesterol: 10 Breakthrough Technologies 2023

New forms of the gene-editing tool could enable treatments for common diseases.

An ALS patient set a record for communicating via a brain implant: 62 words per minute

Brain interfaces could let paralyzed people speak at almost normal speeds.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.