The source of desire has long been elusive, the stuff of poets and musicians. Now, Stanford University researchers have found it doesn’t live in the heart but in a very specific set of cells in the brain. They have located the cellular circuitry that drives the passion of male mice, and learned how to turn it on and off – a discovery that could lead to new treatments and deepen our understanding of this most primal force. “It’s a fundamental behavior that is central to our personal satisfaction, and also the propagation of our species,” said Nirao Shah, Stanford professor of psychiatry and neu...