One Small Fly Will Change Everything We Know About The Brain
Pop quiz: The above image is
A) A weirdly shaped pile of Skittles
B) The Seattle Gum Wall
C) An AI-Generated NFT
D) The thousands of neurons of a fly brain.
Alright, I set you up for that one - of course it's D, although I wouldn't have blamed you for picking C. But now the question is, why am I showing you the picture of a fly brain and why should you care?
💡 This one tiny little fly brain is about to completely change how we understand the human brain - from behavior to disease.
Meet Drosophila melanogaster - the common fruit fly
If you see this fly in your house, you know you've got a problem. The fruit fly (Drosophila melanogaster, sometimes just called Drosophila) loves to eat fruit and vegetables, ripe or rotten. They can also get into other organic matter, like sludge in your drains. They also pose risks to agriculture, though it is the more exotic fruit flies that cause the worst problems for farmers.
And yet this small fly viewed as a pest by humans has actually been a key part of scientific research for over 100 years. Stephanie Mohr, lecturer on genetics at Harvard Medical School, explains in depth that the fly has helped with our understanding of inheritance, developmental biology, cancer, and X-rays - just to name a few!
So what's up with this fly brain?
The brain is one of the most complex organs on earth, with about as many neurons in a human brain as there are stars in the Milky Way. Believe it or not, as advanced as our science is today, we've never mapped out the human brain and we're still learning about the different cell types found in it. Makes the Neuralink sound a lot more like science fiction, doesn't it?
The brain pictured above is a fully mapped adult fruit fly brain, containing around 140,000 neurons. That's barely a drop in the sea of the human brain's neuron count. And yet, it is the first complete brain map for an animal that can walk and see.
For such a small thing, that's huge. And since fruit flies share 60% of their genes with humans, with a 75% parallel of human diseases - in addition to all sorts of behavioral and biological functions - this one little brain is a galactic sized win for neuroscience.
How did science make this map, and why did it take so long?
Mapping neurons in a brain is incredibly complex - so I won't try to offer you a lecture on it. Instead, understand that a brain map like this - also called a connectome - requires tons of 2D images that offer a view of a single "slice" of the brain. These images then get aligned and roughly translated into a 3D model through software developed in part by Google Research.
But that's only the start. The AI behind creating these models is still learning and makes plenty of mistakes (especially because the 2D images aren't perfect). That's when scientists come into play - and utilize web-based software to review, proofread, and edit each neuron to make sure it is accurate and complete.
That amount of work takes thousands of hours - but split between people, the brain was able to be proofread and completed within about four years. Thousands of new neurons were discovered in the process - paving the way for whole new avenues of scientific research for generations to come. If you're interested in the full story, I recommend reading Nature's new feature on the project.
Citizen scientists make a difference
So why am I the one telling you about this project? I'm clearly not sitting here with a Ph.D. in neuroscience. However, I'm proud to say that I was, in fact, part of this project.
You'll find me in the FlyWire Consortium - look for AzureJay (Jaime Skelton). I volunteered my time as a citizen scientist - one of only seventeen for this particular project - helping proofread, identify, and annotate the optic lobe neurons of this little fly brain.
Citizen science is a passion of mine, and I've been working with the Princeton University team for several years now across multiple projects. I don't have a degree in science - just a passion for it. Working on the Flywire connectome has been incredibly meaningful for me, and while I have less time than I used to, I'm still helping the team out - currently working on the "BANC" project. When Pyr (pronounced "peer") is released, I'll be there too - diligently proofreading neurons, learning more about neuroscience, and offering some of my time toward the forever forward march of scientific progress.
Meanwhile, why not take some time to learn about your local insects?
Quiz: Do you know your state insect?
Gallery Credit: Andrew Vale
LOOK: 20 of the biggest insects in the world
Gallery Credit: Andrea Vale