Full wiring diagram of an adult fruit fly brain is out

For the first time in history, scientists have charted each neuron in the brain of an adult animal. It encompasses around 50 million links among almost 140,000 neurons.

The map was developed from the brain of a mature creature: the fruit fly Drosophila melanogaster. This impressive accomplishment records almost 140,000 neurons and 50 million connections, forming a complex map of the fly's brain.

Featured in Nature, the study represents an important advancement in comprehending how brains handle information, influence behavior, and retain memories.

The brain of an adult fruit fly serves as an excellent model for investigating neural systems. Although its brain is significantly smaller and simpler than that of humans, it shows numerous similarities, such as neuron-to-neuron connections and the use of neurotransmitters.

For instance, both the brains of flies and humans utilize dopamine for learning rewards and have similar structural patterns in circuits related to vision and navigation. This positions the fruit fly as an effective instrument for investigating the fundamental principles of brain activity. Employing advanced telomere-to-telomere (T2T) sequencing, scientists discovered more than 8,000 cell types in the fly brain, emphasizing the variety of neural structure even within a comparatively small system.

The consequences of this research are extensive. Researchers aim to reveal the common "rules" that dictate neural wiring throughout the animal kingdom by contrasting the connectivity of the fly brain with that of other species. This map also acts as a foundation for upcoming experiments, enabling researchers to examine how experiences, like learning or social interaction, modify neural circuits. Although human brains are significantly larger and more intricate, this study offers an essential basis for comprehending the basic structure of all brains. According to lead researcher Philipp Schlegel, “Any brain we can genuinely comprehend aids us in understanding all brains.”

Image: FlyWire.ai; Rendering by Philipp Schlegel (University of Cambridge/MRC LMB)