To really understand the human brain, scientists say you'd have to map its wiring. The only problem: there are more than 100 trillion different connections to find, trace and characterize. But a team of scientists has made a big stride toward this goal, a complete wiring diagram of a teeny, tiny brain: the fruit fly larva. With a full map, or connectome, of the larval fruit fly brain, scientists can start to understand how behaviors shape, and are shaped by, the specific wiring of neural circuits. On today's episode, our resident neuroscience aficionado, NPR science correspondent Jon Hamilton, talks over the new findings with Short Wave co-host Emily Kwong, and explains why we big-brained humans ought to care.