(Image via princeton.edu)

Volunteer Writer: Samantha McCarthy

Email: smccarthy12@umassd.edu 

After four years of intricate, ambitious work, scientists could finally reveal the largest brain map- or, scientifically speaking, ‘connectome’-  ever created, with the fruit fly’s brain being showcased in full detail. 

FlyWire, a human-artificial intelligence (AI) collaboration software started by neuroscientists Mala Murthy and Sebastian Seung at Princeton University, profiled nearly 140,000 neurons and about 54.5 million synapses (junctions between two nerve cells). 

While this may seem insignificant, as a fruit fly is not the smartest of animals, humans share 60% of their DNA with small insects and 75% of the genes that cause genetic diseases, according to Princeton University research. Similarly to humans, fruit flies can get drunk, sing songs, and be kept awake with caffeine, according to Smithsonian Magazine.

“You might be asking why we should care about the brain of a fruit fly,” Seung told The Guardian. She continued, “My simple answer is that if we can truly understand how any brain functions, it’s bound to tell us something about all brains.”

This information was presented through nine papers uploaded to the journal Nature. 

Scientists did this by taking electron microscopy images of the fruit fly’s brain. 7,000 images were taken, revealing segments four-millionths of a millimeter wide. 

Afterward, these images were uploaded to form a greater map with the assistance of AI tools. However, AI is imperfect, so the University acquired volunteers to help sort through the database, making over three million manual edits. 

According to ScienceDaily, researchers have formed maps for smaller larval fruit flies in the past, but they are nowhere near as complex as the larval fruit fly brain, which only had 3,000 neurons. 

This research is a significant step in neuroscience, as it will assist scientists in determining the neural pathways that can lead to human behaviors. 

“Fruit flies’ brain architecture can form memories, learn, and engage in complex social behavior. Hence, findings from studies on fruit flies’ brains can often be applied to other animals, including humans,” the FlyWire website states. 

The connectome was tested by creating software that showed sensory signals and presented signals for both sweet and bitter tastes, and, to their excitement, the neurons that would react in a real fly followed suit. 

While this mapping is of a female fruit fly brain, scientists aspire to fully develop a connectome of the male fruit fly brain to understand male-specific fruit fly behaviors, such as singing. 

Scientists have begun to use connectome technology to map the connections of the brain of a mouse- which they are hoping to complete in the next five to ten years. 

As connectome technology develops, researchers aim to map the full human brain. The human brain is about one million times more complex than a fruit fly, with 86 billion neurons and trillions of connections. 

As of today, this cannot come to fruition as mapping would require a memory equivalent to the entire world’s internet traffic for a year. 

While the world of neuroscience still has much work to do to fully understand the workings of the brain- not just the human brain- this is a big step in the right direction for research advancements. 

With a more developed understanding of any brain, neuroscientists can develop a better understanding of the neurons and synapses and their functions. 

“We clearly have a big task ahead of us,” stated Dr. John Ngai, director of the U.S. National Institutes of Health’s Brain Initiative. 

An interactive version of the connectome can be viewed at flywire.ai.