Scientists have fully mapped a fruit fly brain for the first time, uncovering every individual neuron (messenger cell) and how they are wired together. The 3,016 neurons resemble an AI neural network of sorts and between those cells, they discovered 548,000 points of connection, or synapses, where cells transmit chemical messages, thus triggering electrical signals that travel through their wiring. How a brain circuit is structured heavily influences the computations it can perform, and up until this point, researchers have only seen the structure of the roundworm C. elegans, the tadpole of a low chordate and the larva of a marine annelid, all of which only have several hundred neurons. Now they can start gaining a mechanisitic understanding of how the brain actually works. We previously had only limited information on gene expression in the zebrafish brain.