Science reports:

Do rats like to be tickled? The furry rodents can be quite fun-loving, scientists say. And yes, under the right circumstances, they do enjoy a bit of rough-and-tumble play, letting out high-pitched squeaks akin to human laughter. Now, researchers say they have identified the area of the brain responsible for this playfulness.

The discovery, reported today in Neuron, represents “a fantastic step forward” for understanding the neural basis of play and laughter, says Sergio Pellis, a neuroscientist at the University of Lethbridge who was not involved in the study.

Of all mammalian behaviors, play is one of the least understood, says Michael Brecht, a neuroscientist at the Humboldt University of Berlin. “Neuroscience tends to focus very much on aversive things,” he explains, such as the brain regions behind aggression and fear. Play remains a mystery. “There’s relatively little research on positive emotions,” Brecht says, “which I tend to think is a mistake.” [Continue reading…]