A team of researchers led by two Harvard alumni uncover a switch that controls brain states.

Martin Haesemeyer set out to build an artificial neural network that worked differently than fish’s brains, but what he got was a system that almost perfectly mimicked the zebrafish — and that could be a powerful tool for understanding biology.

Researchers have found that when making decisions that are important to the species’ survival, zebrafish choose to mate rather than to flee from a threat.