[Reading Science] The Brain of Drosophila Was Similar to Artificial Intelligence

UK Cambridge University Research Team Successfully Maps Brain of Young Drosophila
Enables Understanding of Animal Sensory Information Processing and Behavior Decision Principles
Supports AI Research and Treatment of Degenerative Brain Diseases like Dementia

Scientists have succeeded in fully mapping the brain structure of the fruit fly, enabling an understanding of how the brain processes information and makes behavioral decisions. This achievement is seen as opening new horizons for brain research necessary to overcome diseases such as dementia and aiding artificial intelligence (AI) research.

A research team from the University of Cambridge in the UK published a paper containing these findings on the 9th in the international journal Science. The team created a complete map of the brain of the fruit fly (scientific name Drosophila melanogaster), which is smaller than a poppy seed, detailing 3,016 densely packed brain neurons and 548,000 synapses connecting them.

The scientific community regards this as another milestone in brain research. Marta Zlatic, a professor of neuroscience at the University of Cambridge and co-author of the paper, explained to the international journal Nature, "This map will be a touchstone for understanding how the brain processes sensory information and translates it into behavior," adding, "Now we have the tools to see what happens to the connectivity of brain cells in degenerative brain diseases such as Alzheimer's and Parkinson's."

Until now, scientists have succeeded in mapping the brains of animals such as the nematode Caenorhabditis elegans, the marine worm Platynereis dumerilii, and the sea squirt larva Ciona intestinalis. The fruit fly has also been considered a suitable model for brain structure research. Its genome map has already been completed, and it has a transparent body. The fruit fly’s brain supports complex and sophisticated behaviors such as learning, spatial navigation, olfaction, and evaluating behavioral risks and benefits. Additionally, its small size makes it an ideal subject for detailed structural analysis with current technology. Albert Cardona, a professor at the University of Cambridge and co-author, said, "I participated in brain research on Caenorhabditis elegans in the 1980s, and with the technology at that time, studying the fruit fly brain structure would have been impossible."

The research team used electron microscopy with nanometer resolution to analyze the brain of a fruit fly that was six hours old. They captured images of the brain over a year and a half, then spent several months using computer programs to accurately identify neurons and synapses, verifying each one individually. The results showed that 93% of the 3,016 neurons were connected to other neurons located on the opposite side of the brain. Most of the unmatched neurons were Kenyon cells, which are key brain cells involved in learning and memory centers.

The team then analyzed the connectivity of each neuron and found that the 548,000 synapses could be grouped into four types. They also discovered that the fruit fly brain is a multilayered structure composed of pathways of varying lengths connecting inputs and outputs. Furthermore, shortcut pathways that bypass some layers existed within the neural network, which was analyzed as the reason why the fruit fly can perform rapid computations despite having a limited number of neurons. Forty-one percent of the fruit fly brain neurons had recurrent loops, providing feedback to higher-level partners. These shortcut pathways and recurrent loops resembled the state-of-the-art artificial neural networks used in AI research.

Professor Zlatic said, "Although this study obtained data from the brain of a single individual, future technological advances will enable research on additional individuals as well as mapping the brain structures of other species," adding, "This can be used to train machine learning to perform learning processes more quickly."

Meanwhile, the research team plans to create a brain map of adult fruit flies, which have more neurons and more complex brains.