A major goal of neuroscience is understanding how all of the brain’s neurons know how to connect to each other to achieve optimum function. Scientists often study the fruit fly Drosophila melanogaster because their brains are “hardwired” (meaning nearly identical). Now, Caltech researchers have determined how part of the fly’s visual system forms, an important piece in understanding the brain’s connectivity. A paper describing the research appears in the journal eLife. The work was done in the laboratory of Kai Zinn, Howard and Gwen Laurie Smits Professor of Biology. Zinn is an affiliated faculty member of Caltech’s Tianqiao and Chrissy Chen Institute for Neuroscience.