Scientists complete the first map of an insect brain, seeking to understand how we think

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The work may inform future brain research and inspire new machine learning architectures

Scientists complete the first map of an insect's brain, in the quest to understand how we think

Researchers have completed the most advanced brain map to date, that of an insect, a landmark achievement in neuroscience that brings scientists closer to science. true understanding of the mechanism of thought, as published in the magazine 'Science'.

The international team led by Johns Hopkins University (United States) and the University of Cambridge (United Kingdom) developed the report. Here's an astonishingly detailed diagram mapping every neural connection in the brain of a larval fruit fly, an archetypal scientific model with brains comparable to humans.

The work will probably serve more It will form the basis for future research on the brain and will inspire further research. new machine learning architectures.

“If we want to understand who we are and how we think, part of it is understanding the mechanism of thought,” explains lead author Joshua T. Vogelstein, a biomedical engineer. “I'm from Johns Hopkins specializing in data-driven projects like connectomics, the study of connections in the nervous system–and the key to that is knowing how neurons connect to each other.”

The most complete and extensive map ever made

The first attempt to map a brain –a 14-year study of the roundworm started in the 1970s–resulted in a partial map and a Nobel Prize. Since then, partial connectomes have been mapped in many systems, including flies, mice, and even humans, but these reconstructions often represent only a small fraction of the total brain.

Complete connectomes have only been generated from several small species with a few hundred or thousands of neurons. In their bodies: a roundworm, a sea squirt larva, and a marine annelid larva.

 This team's connectome of a pup fruit fly, the larva of 'Drosophila melanogaster', is the most complete and extensive map ever madefrom the brain of an insect. It includes 3,016 neurons and all the connections between them: 548,000.

“It's been 50 years and this is the first brain connectome. It's a flag in the arena of “So we can do it,” Vogelstein points out, “everything has worked its way up to this.”

More than a decade

Mapping entire brains is difficult ;easy and time consuming, even with the best modern technology. To get a complete picture at the cellular level of a brain it is necessary to divide it into hundreds or thousands of individual tissue samples, all of which have to be analyzed with electron microscopes before the laborious process of reconstructing all of them. He assembled those pieces, neuron by neuron, into a complete and accurate portrait of a brain.

It took a while to get there. more than a decade doing it with the breeding of fruit flies. The brain of a mouse is estimated to be a million times larger than that of a baby fruit fly, which means that the possibility of mapping anything resembling a human brain is unlikely in a future. near future, perhaps not even in our lifetimes.

The team chose the best. I purposely named the larva of the fruit fly because, for an insect, thespecies shares much of its fundamental biology with humans, including a comparable genetic basis.

In addition, it has rich learning and decision-making behavior, making it a useful model organism in neuroscience. For practical purposes, its relatively compact brain allows imaging and reconstructing its circuitry in a reasonable amount of time.

Even so, the work took some time. 12 years at Cambridge and Johns Hopkins Universities. Only imaging took the time. about one day per neuron.

Neuron by neuron

Cambridge researchers created the high-resolution images of the brain and scanned them manually to find individual neurons, rigorously tracing each of them and relating their synaptic connections.

Cambridge relented. the data to Johns Hopkins, where the team what happened They spent more than three years using the original code they created to analyze brain connectivity. The Johns Hopkins team developed the He developed techniques for finding groups of neurons based on shared connectivity patterns, and then analyzed their findings. how information could propagate through the brain.

In the end, the entire team plotted the game. He made a graph of each neuron and each connection, and classified the cells. He separated each neuron by the function it performs in the brain. They found that the most active circuits in the brain were the ones going to and from the neurons in the learning center.

The methods developed by Johns Hopkins are applicable to any project brain connection, and your code is ready. It will be available to anyone trying to map an even larger animal brain, said Vogelstein, adding that it is not yet available. So despite the challenges, scientists are expected to take on the mouse, possibly in the next decade. Other teams are already working on a map of the adult fruit fly brain.

Co-first author Benjamin Pedigo, a Johns Hopkins PhD candidate in biomedical engineering, hopes that team code can help reveal important comparisons between adult and larval brain connections. As connectomes are generated from more larvae and related species, Pedigo hopes that his analytical techniques will provide a better understanding of variations in brain wiring.

Implications for the code of brains. I mean human

The work with fruit fly larvae showed that it was not possible. circuitry features strikingly reminiscent of prominent and powerful machine learning architectures. The team hopes that continued study will reveal even more computational principles and may inspire new artificial intelligence systems.

“What we've learned about the fruit fly code