Decoding the Fruit Fly: Scientists Reveal The First Comprehensive Neural Map of an Insect Brain

By on March 20, 2023

Good news guys? Researchers have announced the creation of the first-ever comprehensive map of the brain of an insect! The map includes all of the neurons and connecting synapses of the fruit fly, Drosophila melanogaster. Published in Science (reference), the research provides a brain-wiring diagram (also known as the connectome as long-time readers will know), of a complex animal for the first time. The map shows all 3,016 neurons and 548,000 synapses in the brain of a young Drosophila. Yes, one of those. 


The insect’s brain is smaller than a poppy seed.

See also: Can Mind Uploading Ever Work?

The researchers spent a year and a half capturing images of the brain of a single six-hour-old Drosophila larva with a nanometer-resolution electron microscope. They then pinpointed the neurons and synapses, and spent months manually checking them. The authors identified 3,016 neurons, most of which were paired with a partner neuron in the opposite brain hemisphere. The researchers traced each neuron’s connections and annotated 548,000 synapses, which could be grouped into four types.

For context, the human brain is believed to contain roughly 100 billion neurons. So, rest assured, you are cleverer than a fly. Or, at least, a Drosophila.

The map is a milestone in understanding how the brain processes the flow of sensory information and translates it into action. Marta Zlatic, a co-author of the paper, said of the achievement: “Now we have a reference brain. We can look at what happens to connectivity in models of Alzheimer’s and Parkinson’s diseases and of any degenerative disease.”

Until now, scientists had mapped the connectomes of only the worms Caenorhabditis elegans and Platynereis dumerilii, and the larva of the sea squirt Ciona intestinalis. Drosophila was an ideal model for connectome studies because scientists have already sequenced its genome, and the larvae have transparent bodies. Fruit flies also exhibit sophisticated behaviors, including learning, navigating landscapes, processing smells, and weighing the risks and benefits of an action.

Incredibly, these neurons also, presumably, provide the seat of the fly’s sentience and self-awareness. 

Could we simulate these same neurons in a computer program and potentially create a living being within a simulation? If the connectome is available publicly, could we ask ChatGPT to do this for us and have a “working” fly of our own in an afternoon?

Those frequent visitors to the site will know this is unlikely – the brain is far more complex than a simple “mind-map” of neurons. Even the neurons themselves are complex machines capable of computation and more that we don’t understand.

See also: This Amazing Feature of the Brain Lets Us Process Information Even More Efficiently: Dendritic Computation

That’s before we even consider the rules that govern when and how neurons fire (which we haven’t perfectly modelled), the laws of plasticity, the role of neurotransmitters and glial cells… Suffice to say that this does NOT represent a total model or understanding of the insect brain.

But it’s still mighty impressive. And to see how this information is organised is an incredible opportunity.

The next step is to map the brain of the adult Drosophila, which is more complex and has more neurons. The researchers say that technological advances will allow mapping of more flies — and eventually of other species.

About Adam Sinicki

Adam Sinicki, AKA The Bioneer, is a writer, personal trainer, author, entrepreneur, and web developer. I've been writing about health, psychology, and fitness for the past 10+ years and have a fascination with the limits of human performance. When I'm not running my online businesses or training, I love sandwiches, computer games, comics, and hanging out with my family.


  1. Dave says:

    Time flies like an arrow, fruit flies like a banana

  2. alex says:

    Thats kinda cool, but when you say “…Incredibly, these neurons also, presumably, provide the seat of the fly’s sentience and self-awareness. …” I’m not sure how much self awareness or sentience a fly has. Back in the 90’s I read a book on cybernetics and their idea was that consciousness was an “emergent property”, a system being more then its parts, which makes me wonder if a super large brained fly actually wood develop a view of itself the way dolphins and humans do.
    On the other hand, maybe they do not have the right brain structure- Parrot brains are not all that big but avian brains pack a lot into what they have. I know chickens have to see a behavior before they will do it, I’ve had to ‘peck’ at feed with my finger so new hatched chicks will start eating, and dip their beak in the water, but when they see one do it they ALL get it as if by magic.

  3. NotTheDoctor says:

    This is so cool! Hot take; while I LOVE all the Batman-related content, it’s really cool every now and then when you dive into more off-the-wall topics, especially brain/computer-related.

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