Sex comprises an intricate tangle of impulses and interactions between partners. Neuroscientists have learned a great deal about the neural mechanisms underlying sex, but questions about the processes that control the sequence of events during sex remain unanswered. While past research has identified the regions of the brain that control how mice initiate sex, other steps of copulation are still mysteries. A team of researchers in China and Japan have investigated which brain regions and neurotransmitters are responsible for different phases during sex. A paper published March 19 in the journal Neuron describes what exactly goes on in a mouse brain during sex.