https://phys.org/news/2018-06-human-artificial-intelligence-complexity-brain.html

"To truly understand the workings of the brain, even for organisms as small as the fruit fly, we need to zoom in on each and every individual cell," explains prof. Stein Aerts (VIB-KU Leuven). "All organs and tissues are composed of many different cells that communicate with each other to perform their specific functions. Although they share the same DNA, they all express a distinct set of genes, and to understand what is really going on, we need to know which cells are doing what and when."

Working with fruit flies as model organisms, the scientists took the challenge head on, immediately starting with the most complex organ of all—the brain.