Giant findings for fly brain
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Scientists have unwound the intricate wiring of a fruit fly’s brain.
An international team of scientists has successfully mapped the brain of a fruit fly (Drosophila melanogaster) - an enormous achievement in neuroscience.
The research project provides the most detailed brain map, or ‘connectome’, ever completed for any organism.
This milestone is expected to enhance the understanding of brain functions and help pave the way for mapping the brains of other species.
The fruit fly Drosophila melanogaster has been a staple in scientific research for over a century due to its relatively simple genetics and short life cycle, making it ideal for studying fundamental biological processes.
As a model organism, it shares many genetic similarities with humans, allowing researchers to explore a wide range of topics such as development, neurobiology, and disease.
Its genome has been fully sequenced in the past, allowing the creation of sophisticated genetic tools to understand and modify it.
The fruit fly’s simplicity, combined with the complexity of its neural circuits, makes it particularly valuable for investigating how brains are wired and how this wiring influences behaviour.
The brain map, which details nearly 140,000 neurons and over 54.5 million synapses, offers even deeper insight into the fruit fly’s neural connections.
The map, known as FlyWire, is the result of a collaboration between multiple scientists across several countries and institutions, co-led by neuroscientists Mala Murthy and Sebastian Seung of Princeton University.
The team spent over four years developing the connectome using high-resolution electron microscopy images of the fly's brain, followed by extensive manual editing to ensure accuracy.
More than three million corrections were made with the help of volunteers.
The researchers say they are amazed at the complexity revealed by the connectome. Among many early findings, it reveals that brain cells thought to be involved in specific sensory circuits often responded to multiple senses, including vision, hearing, and touch.
“It’s astounding how interconnected the brain is,” Murphy remarked.
The research has already led to new discoveries, detailed in a package of nine papers about the data published in Nature.
In one study, researchers used the connectome to simulate the entire fruit fly brain, testing neural circuits linked to taste. The virtual model accurately predicted how real flies would respond to sweet and bitter stimuli, proving more than 90 per cent accurate.
Despite these advancements, the FlyWire project has limitations.
The connectome was created from a single female fly, which means that it does not account for variations between individuals.
Furthermore, it only maps chemical synapses and lacks information about electrical connectivity or how neurons communicate outside of synapses.
Murthy and her team plan to create a connectome for male flies to study male-specific behaviours, such as courtship songs.
“We’re not done, but it’s a big step,” researcher Davi Bock says.
FlyWire’s brain map is already available for exploration by researchers worldwide, opening new avenues for studying neural circuits.
By understanding the neural connections in simple organisms like fruit flies, scientists hope to eventually unravel more complex brains, providing insights into diseases and conditions that affect humans.