NYTimes.com: How to Map a Fly Brain in 20 Million Easy Steps

[John Clark]

Up to now the only complete connectome ( map of internal brain connections) belong to the nearly microscopic worm C. elegans she had a brain of only 302 neurons but Gerald Rubin wanted to do better so in 2014 he started the map all the connections in a single 5 day old female fruit fly which contained 25,000 neurons and 20 million synapses. Rubin said "I don’t want to offend any of my worm colleagues, but I think flies are the simplest brain that actually does interesting, complex behavior”. The device he used is called a "focused-ion beam scanning electron microscope", it makes an image at super high resolution of a layer of the brain and at the same time it vaporizees the ultra thin layer and exposes the layer underneath it. He had to do this millions of times before he had detailed pictures of the entire brain, so he had to be super careful because once a layer had been vaporized there's no way to get it back if you made a blurry image, so you'd have to scrap all your work and start all over again.  It must've been nerve-racking. Another neuroscientist said  "You’re simultaneously imaging and cutting off little slices of the fly brain, so they don’t exist after you’re done. So if you screw something up, you’re done. Your goose is cooked — or your fly brain is cooked.”

Rubin's team then had to use AI software running on a supercomputer to connect all the images together into a 3-D volume and trace the twisty path of every neuron. They publish their finished results online, although it's so long it's more like a book than a paper. Another  Neuroscientist said of this work "You’re telling me you can give me the wiring diagram for something like this? This is better industrial espionage than you could get by getting insights into the Apple iPhone.”

John K Clark

From The New York Times:

How to Map a Fly Brain in 20 Million Easy Steps

An enormous new analysis of the wiring of the fruit fly brain is a milestone for the young field of modern connectomics, scientists say.

https://www.nytimes.com/2021/10/26/science/drosophila-fly-brain-connectome.html?smid=em-share