Scientists Map Fruit Fly Brain in Neurobiological Milestone

By Will Dunham

WASHINGTON – Scientists announced a significant breakthrough in neurobiological research with the completion of mapping the entire brain of an adult fruit fly. This achievement could shed light on brain function across various species, including humans.

The research unveiled over 50 million connections among more than 139,000 neurons in the insect, scientifically known as Drosophila melanogaster, which is frequently used in neurobiological studies. The goal was to understand how brains are structured and the signals that underlie healthy brain functions, potentially paving the way for mapping the brains of other species.

Princeton University’s professor of neuroscience and computer science, Sebastian Seung, one of the co-leaders of the project, emphasized the broader implications: "If we can truly understand how any brain functions, it will likely provide insights applicable to all brains."

While some may be more inclined to swat flies than study them, the aesthetic beauty of the fruit fly brain, measuring less than 0.04 inches (1 mm) wide, captured the interest of some researchers. "It’s beautiful," remarked Gregory Jefferis, a neuroscientist from the University of Cambridge and co-leader of the research.

The researchers created a wiring diagram, referred to as a connectome, for the adult fruit fly’s brain. Earlier research had focused on simpler organisms, like the worm Caenorhabditis elegans, and the larval stage of the fruit fly. The adult fruit fly’s more complex behaviors provided a richer subject for exploration.

Mala Murthy, another co-leader of the research and a neuroscientist at Princeton, explained, "One of the major questions we’re addressing is how the wiring in the brain, its neurons, and connections can give rise to animal behavior." She pointed out that fruit flies serve as an important model in neuroscience, solving many of the same challenges as humans. Their capabilities include sophisticated behaviors such as walking, flying, learning, memory, navigation, feeding, and even social interactions.

The research comprised several studies that examined various brain circuits. One study investigated the circuits related to walking and discovered the mechanisms that allow flies to stop. Another focused on the fly’s taste network and grooming behaviors, such as how they use their legs to clean dirt from their antennae. Additional studies delved into the visual system, particularly how the fly’s eyes process motion and color, and explored the flow of information across the brain, identifying a significant collection of "hub neurons" that enhance communication.

The researchers meticulously detailed the structure of the brain’s hemispheres and behavioral circuits, identified the full range of cell classes, differentiated types of neurons, and mapped the synapses connecting these nerve cells as well as the chemical substances secreted by the neurons.

The collaborative effort was part of an extensive international team of scientists known as the FlyWire Consortium.