Scientists map fruit fly brain to reveal insights into neural circuits

A team of scientists supported by the National Institutes of Health’s (NIH) BRAIN Initiative, including Dr. Davi Bock, associate professor of neuroscience at UVM’s Robert Lerner School of Medicine, has recently made significant advances in research. Ta. A neurobiological study successfully mapped the entire brain of Drosophila melanogaster, better known as Drosophila melanogaster.

The study, published in Nature and titled “Whole Brain Annotation and Multi-Connectome Cell Typing in Drosophila,” is a “consensus cell type atlas” for understanding the different cell types in the Drosophila brain. In other words, we have established a comprehensive guide. The Drosophila brain contains approximately 130,000 neurons (the human brain contains 86 billion neurons). has 100 million neurons).

The underlying electron microscopy dataset of the Whole Brain Connectome (FAFB, or known as the “Full Adult Fly Brain”) captures the detailed shape of every neuron in the fly brain and every synaptic connection between them. to identify and catalog all cell types. In your brain.

This complete map will help researchers identify how different circuits work together to control behaviors such as motor control, courtship, decision-making, memory, learning, and navigation.

“If we want to understand how the brain works, we need to understand mechanistically how all the neurons work together to make thinking possible,” said study co-principal Gregory. Dr. Jefferies said.

“For most brains, we don’t know how these networks work. Now, we have this complete wiring diagram, an important step in understanding complex brain function.” In fact, using our data shared online during the study, we collaborated with other scientists who have already made attempts to simulate how the fly’s brain responds to the outside world. It’s starting. ”

“To start simulating the brain digitally, we need to know not only the structure of the brain, but also how neurons work and turn each other on and off,” Jeffries said.

“Using data shared online during the study, other scientists have already begun attempts to simulate how the fly brain responds to the outside world. Although this is an important start, In order to do so, we need to collect different types of data to produce reliable simulations of how the brain works. ”

Similar studies have been performed in simpler organisms such as the nematode C. elegans and Drosophila larvae, but more complex behaviors can be studied in Drosophila adults. Although the fruit fly brain is clearly less complex than the human or even mouse brain, the implications of this study are profound.

There are significant similarities in the way neural circuits in all species process information. This research allows principles of information processing to be identified in simpler model organisms and explored in larger brains.

Professor Bock said that although scientists are currently unable to scale up this approach to human brains, this achievement is a notable step towards a complete connectome in the mouse brain.

“This type of research (being conducted throughout this field of connectomics) is advancing cutting-edge technology at a once-in-a-century pace, and is improving both the shape and connectivity of individual neurons in the complete human brain. We were able to study the adult Drosophila melanogaster, a fairly sophisticated animal, and use cutting-edge software analysis to annotate and mine the resulting connectome.” Bock said.

“Light microscopy, even using polychromatic fluorescence, and classical Golgi and related approaches do not offer this capability.

“Achieving this feat at the scale of the whole brain in an important genetic model organism like Drosophila represents a remarkable advance in the field.”

The study leverages tools and data generated by the FlyWire consortium, which includes research leaders such as UVM’s Bock. Dr Gregory Jefferis and Dr Philipp Schlegel from the MRC Institute of Molecular Biology and the University of Cambridge. and Dr. Sebastian Sun and Dr. Mara Murthy of Princeton University.

The consortium used electron microscopy brain images previously produced in Bock’s lab to create a detailed map of the connections between neurons throughout the adult female Drosophila brain. This map contains approximately 50 million chemical synapses between the fly’s aforementioned 139,255 neurons.

The researchers also added information about different cell types, nerves, and developmental lineages, as well as predictions about the neurotransmitters used by neurons. FlyWire’s Connectome Data Explorer open access data analysis tool can be accessed, downloaded, and viewed interactively. All of this is done in the spirit of encouraging team science. The study is detailed in the accompanying Nature paper, “Neural wiring diagram of the adult brain.”

“We’ve opened up our entire database and made it freely available to all researchers. This will be transformational for neuroscientists seeking to better understand how the healthy brain works. I hope so,” Murthy said. “In the future, we hope to be able to compare what happens when problems occur in the brain, for example with mental health conditions.”

By tracing connections from sensory cells to motor neurons, researchers are able to uncover potential circuit mechanisms that control Drosophila behavior, which could help us understand the complexity of human cognition and behavior. This is an important step towards achieving this goal.

“This tiny fruit fly is amazingly sophisticated and has long served as a powerful model for understanding the biological basis of behavior,” said Dr. John Guy, director of The BRAIN Initiative at NIH.

“This milestone not only provides researchers with a new toolset for understanding how circuits in the brain drive behavior, but also extends the ongoing efforts to map brain connectivity in large mammals and humans. We will play an important role as a pioneer in this initiative.”